quincy 17.2.6 - write performance continuously slowing down until OSD restart needed - ceph-users

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Nikola Ciprich

2 May 2023 2 May '23

10:32 a.m.

Hello dear CEPH users and developers, we're dealing with strange problems.. we're having 12 node alma linux 9 cluster, initially installed CEPH 15.2.16, then upgraded to 17.2.5. It's running bunch of KVM virtual machines accessing volumes using RBD. everything is working well, but there is strange and for us quite serious issue - speed of write operations (both sequential and random) is constantly degrading drastically to almost unusable numbers (in ~1week it drops from ~70k 4k writes/s from 1 VM to ~7k writes/s) When I restart all OSD daemons, numbers immediately return to normal.. volumes are stored on replicated pool of 4 replicas, on top of 7*12 = 84 INTEL SSDPE2KX080T8 NVMEs. I've updated cluster to 17.2.6 some time ago, but the problem persists. This is especially annoying in connection with https://tracker.ceph.com/issues/56896 as restarting OSDs is quite painfull when half of them crash.. I don't see anything suspicious, nodes load is quite low, no logs errors, network latency and throughput is OK too Anyone having simimar issue? I'd like to ask for hints on what should I check further.. we're running lots of 14.2.x and 15.2.x clusters, none showing similar issue, so I'm suspecting this is something related to quincy thanks a lot in advance with best regards nikola ciprich -- ------------------------------------- Ing. Nikola CIPRICH LinuxBox.cz, s.r.o. 28.rijna 168, 709 00 Ostrava tel.: +420 591 166 214 fax: +420 596 621 273 mobil: +420 777 093 799 www.linuxbox.cz mobil servis: +420 737 238 656 email servis: servis(a)linuxbox.cz -------------------------------------

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Igor Fedotov

2 May 2 May

4:41 p.m.

Hi Nikola, I'd suggest to start monitoring perf counters for your osds. op_w_lat/subop_w_lat ones specifically. I presume they raise eventually, don't they? Does subop_w_lat grow for every OSD or just a subset of them? How large is the delta between the best and the worst OSDs after a one week period? How many "bad" OSDs are at this point? And some more questions: How large are space utilization/fragmentation for your OSDs? Is the same performance drop observed for artificial benchmarks, e.g. 4k random writes to a fresh RBD image using fio? Is there any RAM utilization growth for OSD processes over time? Or may be any suspicious growth in mempool stats? As a blind and brute force approach you might also want to compact RocksDB through ceph-kvstore-tool and switch bluestore allocator to bitmap (presuming default hybrid one is effective right now). Please do one modification at a time to realize what action is actually helpful if any. Thanks, Igor On 5/2/2023 11:32 AM, Nikola Ciprich wrote:

...

Nikola Ciprich

8:02 p.m.

Hello Igor, On Tue, May 02, 2023 at 05:41:04PM +0300, Igor Fedotov wrote:

...

Hi Nikola, I'd suggest to start monitoring perf counters for your osds. op_w_lat/subop_w_lat ones specifically. I presume they raise eventually, don't they?

OK, starting collecting those for all OSDs.. currently values for avgtime are around 0.0003 for subop_w_lat and 0.001-0.002 for op_w_lat I guess it'll need some time to find some trend, so I'll check tomorrow

...

Does subop_w_lat grow for every OSD or just a subset of them? How large is the delta between the best and the worst OSDs after a one week period? How many "bad" OSDs are at this point?

I'll see and report

...

And some more questions: How large are space utilization/fragmentation for your OSDs?

OSD usage is around 16-18%. fragmentation should not be very bad, this cluster is deployed for few months only

...

Is the same performance drop observed for artificial benchmarks, e.g. 4k random writes to a fresh RBD image using fio?

will check again when the slowdown occurs and report

...

Is there any RAM utilization growth for OSD processes over time? Or may be any suspicious growth in mempool stats?

nope, RAM usage seems to be pretty constant. hewever, probably worh noting, historically we're using following OSD options: ceph config set osd bluestore_rocksdb_options compression=kNoCompression,max_write_buffer_number=32,min_write_buffer_number_to_merge=2,recycle_log_file_num=32,compaction_style=kCompactionStyleLevel,write_buffer_size=67108864,target_file_size_base=67108864,max_background_compactions=31,level0_file_num_compaction_trigger=8,level0_slowdown_writes_trigger=32,level0_stop_writes_trigger=64,max_bytes_for_level_base=536870912,compaction_threads=32,max_bytes_for_level_multiplier=8,flusher_threads=8,compaction_readahead_size=2MB ceph config set osd bluestore_cache_autotune 0 ceph config set osd bluestore_cache_size_ssd 2G ceph config set osd bluestore_cache_kv_ratio 0.2 ceph config set osd bluestore_cache_meta_ratio 0.8 ceph config set osd osd_min_pg_log_entries 10 ceph config set osd osd_max_pg_log_entries 10 ceph config set osd osd_pg_log_dups_tracked 10 ceph config set osd osd_pg_log_trim_min 10 so maybe I'll start resetting those to defaults (ie enabling cache autotune etc) as a first step..

...

As a blind and brute force approach you might also want to compact RocksDB through ceph-kvstore-tool and switch bluestore allocator to bitmap (presuming default hybrid one is effective right now). Please do one modification at a time to realize what action is actually helpful if any.

will do.. thanks again for your hints BR nik

...

Thanks, Igor On 5/2/2023 11:32 AM, Nikola Ciprich wrote:

-- ------------------------------------- Ing. Nikola CIPRICH LinuxBox.cz, s.r.o. 28.rijna 168, 709 00 Ostrava tel.: +420 591 166 214 fax: +420 596 621 273 mobil: +420 777 093 799 www.linuxbox.cz mobil servis: +420 737 238 656 email servis: servis(a)linuxbox.cz -------------------------------------

Igor Fedotov

3 May 3 May

12:10 p.m.

On 5/2/2023 9:02 PM, Nikola Ciprich wrote:

...

hewever, probably worh noting, historically we're using following OSD options: ceph config set osd bluestore_rocksdb_options compression=kNoCompression,max_write_buffer_number=32,min_write_buffer_number_to_merge=2,recycle_log_file_num=32,compaction_style=kCompactionStyleLevel,write_buffer_size=67108864,target_file_size_base=67108864,max_background_compactions=31,level0_file_num_compaction_trigger=8,level0_slowdown_writes_trigger=32,level0_stop_writes_trigger=64,max_bytes_for_level_base=536870912,compaction_threads=32,max_bytes_for_level_multiplier=8,flusher_threads=8,compaction_readahead_size=2MB ceph config set osd bluestore_cache_autotune 0 ceph config set osd bluestore_cache_size_ssd 2G ceph config set osd bluestore_cache_kv_ratio 0.2 ceph config set osd bluestore_cache_meta_ratio 0.8 ceph config set osd osd_min_pg_log_entries 10 ceph config set osd osd_max_pg_log_entries 10 ceph config set osd osd_pg_log_dups_tracked 10 ceph config set osd osd_pg_log_trim_min 10 so maybe I'll start resetting those to defaults (ie enabling cache autotune etc) as a first step..

Generally I wouldn't recommend using non-default settings unless there are explicit rationales. So yeah better to revert to defaults whenever possible. I doubt this is a root cause for your issue though..

...

> > Thanks, > > Igor > > On 5/2/2023 11:32 AM, Nikola Ciprich wrote: >> Hello dear CEPH users and developers, >> >> we're dealing with strange problems.. we're having 12 node alma linux 9 cluster, >> initially installed CEPH 15.2.16, then upgraded to 17.2.5. It's running bunch >> of KVM virtual machines accessing volumes using RBD. >> >> everything is working well, but there is strange and for us quite serious issue >> - speed of write operations (both sequential and random) is constantly degrading >> drastically to almost unusable numbers (in ~1week it drops from ~70k 4k writes/s >> from 1 VM to ~7k writes/s) >> >> When I restart all OSD daemons, numbers immediately return to normal.. >> >> volumes are stored on replicated pool of 4 replicas, on top of 7*12 = 84 >> INTEL SSDPE2KX080T8 NVMEs. >> >> I've updated cluster to 17.2.6 some time ago, but the problem persists. This is >> especially annoying in connection with https://tracker.ceph.com/issues/56896 >> as restarting OSDs is quite painfull when half of them crash.. >> >> I don't see anything suspicious, nodes load is quite low, no logs errors, >> network latency and throughput is OK too >> >> Anyone having simimar issue? >> >> I'd like to ask for hints on what should I check further.. >> >> we're running lots of 14.2.x and 15.2.x clusters, none showing similar >> issue, so I'm suspecting this is something related to quincy >> >> thanks a lot in advance >> >> with best regards >> >> nikola ciprich >> >> >> > -- > Igor Fedotov > Ceph Lead Developer > > Looking for help with your Ceph cluster? Contact us at https://croit.io > > croit GmbH, Freseniusstr. 31h, 81247 Munich > CEO: Martin Verges - VAT-ID: DE310638492 > Com. register: Amtsgericht Munich HRB 231263 > Web: https://croit.io | YouTube: https://goo.gl/PGE1Bx >

Nikola Ciprich

8 May 8 May

9:13 p.m.

Hello Igor, so I was checking the performance every day since Tuesday.. every day it seemed to be the same - ~ 60-70kOPS on random write from single VM yesterday it finally dropped to 20kOPS today to 10kOPS. I also tried with newly created volume, the result (after prefill) is the same, so it doesn't make any difference.. so I reverted all mentioned options to their defaults and restarted all OSDs. performance immediately returned to better values (I suppose this is again caused by the restart only) good news is, that setting osd_fast_shutdown_timeout to 0 really helped with OSD crashes during restarts, which speeds it up a lot.. but I have some new crashes, more on this later..

...

I'd suggest to start monitoring perf counters for your osds. op_w_lat/subop_w_lat ones specifically. I presume they raise eventually, don't they?

OK, starting collecting those for all OSDs..

I have hour samples of all OSDs perf dumps loaded in DB, so I can easily examine, sort, whatever..

...

currently values for avgtime are around 0.0003 for subop_w_lat and 0.001-0.002 for op_w_lat

OK, so there is no visible trend on op_w_lat, still between 0.001 and 0.002 subop_w_lat seems to have increased since yesterday though! I see values from 0.0004 to as high as 0.001 If some other perf data might be interesting, please let me know.. During OSD restarts, I noticed strange thing - restarts on first 6 machines went smooth, but then on another 3, I saw rocksdb logs recovery on all SSD OSDs. but first didn't see any mention of daemon crash in ceph -s later, crash info appeared, but only about 3 daemons (in total, at least 20 of them crashed though) crash report was similar for all three OSDs: [root@nrbphav4a ~]# ceph crash info 2023-05-08T17:45:47.056675Z_a5759fe9-60c6-423a-88fc-57663f692bd3 { "backtrace": [ "/lib64/libc.so.6(+0x54d90) [0x7f64a6323d90]", "(BlueStore::_txc_create(BlueStore::Collection*, BlueStore::OpSequencer*, std::__cxx11::list<Context*, std::allocator<Context*> >*, boost::intrusive_ptr<TrackedOp>)+0x413) [0x55a1c9d07c43]", "(BlueStore::queue_transactions(boost::intrusive_ptr<ObjectStore::CollectionImpl>&, std::vector<ceph::os::Transaction, std::allocator<ceph::os::Transaction> >&, boost::intrusive_ptr<TrackedOp>, ThreadPool::TPHandle*)+0x22b) [0x55a1c9d27e9b]", "(ReplicatedBackend::submit_transaction(hobject_t const&, object_stat_sum_t const&, eversion_t const&, std::unique_ptr<PGTransaction, std::default_delete<PGTransaction> >&&, eversion_t const&, eversion_t const&, std::vector<pg_log_entry_t, std::allocator<pg_log_entry_t> >&&, std::optional<pg_hit_set_history_t>&, Context*, unsigned long, osd_reqid_t, boost::intrusive_ptr<OpRequest>)+0x8ad) [0x55a1c9bbcfdd]", "(PrimaryLogPG::issue_repop(PrimaryLogPG::RepGather*, PrimaryLogPG::OpContext*)+0x38f) [0x55a1c99d1cbf]", "(PrimaryLogPG::simple_opc_submit(std::unique_ptr<PrimaryLogPG::OpContext, std::default_delete<PrimaryLogPG::OpContext> >)+0x57) [0x55a1c99d6777]", "(PrimaryLogPG::handle_watch_timeout(std::shared_ptr<Watch>)+0xb73) [0x55a1c99da883]", "/usr/bin/ceph-osd(+0x58794e) [0x55a1c992994e]", "(CommonSafeTimer<std::mutex>::timer_thread()+0x11a) [0x55a1c9e226aa]", "/usr/bin/ceph-osd(+0xa80eb1) [0x55a1c9e22eb1]", "/lib64/libc.so.6(+0x9f802) [0x7f64a636e802]", "/lib64/libc.so.6(+0x3f450) [0x7f64a630e450]" ], "ceph_version": "17.2.6", "crash_id": "2023-05-08T17:45:47.056675Z_a5759fe9-60c6-423a-88fc-57663f692bd3", "entity_name": "osd.98", "os_id": "almalinux", "os_name": "AlmaLinux", "os_version": "9.0 (Emerald Puma)", "os_version_id": "9.0", "process_name": "ceph-osd", "stack_sig": "b1a1c5bd45e23382497312202e16cfd7a62df018c6ebf9ded0f3b3ca3c1dfa66", "timestamp": "2023-05-08T17:45:47.056675Z", "utsname_hostname": "nrbphav4h", "utsname_machine": "x86_64", "utsname_release": "5.15.90lb9.01", "utsname_sysname": "Linux", "utsname_version": "#1 SMP Fri Jan 27 15:52:13 CET 2023" } I was trying to figure out why this particular 3 nodes could behave differently and found out from colleagues, that those 3 nodes were added to cluster lately with direct install of 17.2.5 (others were installed 15.2.16 and later upgraded) not sure whether this is related to our problem though.. I see very similar crash reported here: https://tracker.ceph.com/issues/56346 so I'm not reporting.. Do you think this might somehow be the cause of the problem? Anything else I should check in perf dumps or elsewhere? with best regards nik -- ------------------------------------- Ing. Nikola CIPRICH LinuxBox.cz, s.r.o. 28.rijna 168, 709 00 Ostrava tel.: +420 591 166 214 fax: +420 596 621 273 mobil: +420 777 093 799 www.linuxbox.cz mobil servis: +420 737 238 656 email servis: servis(a)linuxbox.cz -------------------------------------

Igor Fedotov

9:33 p.m.

Hey Nikola, On 5/8/2023 10:13 PM, Nikola Ciprich wrote:

...

OK, starting collecting those for all OSDs.. I have hour samples of all OSDs perf dumps loaded in DB, so I can easily examine, sort, whatever..

You didn't reset the counters every hour, do you? So having average subop_w_latency growing that way means the current values were much higher than before. Curious if subop latencies were growing for every OSD or just a subset (may be even just a single one) of them? Next time you reach the bad state please do the following if possible: - reset perf counters for every OSD - leave the cluster running for 10 mins and collect perf counters again. - Then start restarting OSD one-by-one starting with the worst OSD (in terms of subop_w_lat from the prev step). Wouldn't be sufficient to reset just a few OSDs before the cluster is back to normal?

...

currently values for avgtime are around 0.0003 for subop_w_lat and 0.001-0.002 for op_w_lat

OK, so there is no visible trend on op_w_lat, still between 0.001 and 0.002 subop_w_lat seems to have increased since yesterday though! I see values from 0.0004 to as high as 0.001 If some other perf data might be interesting, please let me know.. During OSD restarts, I noticed strange thing - restarts on first 6 machines went smooth, but then on another 3, I saw rocksdb logs recovery on all SSD OSDs. but first didn't see any mention of daemon crash in ceph -s later, crash info appeared, but only about 3 daemons (in total, at least 20 of them crashed though) crash report was similar for all three OSDs: [root@nrbphav4a ~]# ceph crash info 2023-05-08T17:45:47.056675Z_a5759fe9-60c6-423a-88fc-57663f692bd3 { "backtrace": [ "/lib64/libc.so.6(+0x54d90) [0x7f64a6323d90]", "(BlueStore::_txc_create(BlueStore::Collection*, BlueStore::OpSequencer*, std::__cxx11::list<Context*, std::allocator<Context*> >*, boost::intrusive_ptr<TrackedOp>)+0x413) [0x55a1c9d07c43]", "(BlueStore::queue_transactions(boost::intrusive_ptr<ObjectStore::CollectionImpl>&, std::vector<ceph::os::Transaction, std::allocator<ceph::os::Transaction> >&, boost::intrusive_ptr<TrackedOp>, ThreadPool::TPHandle*)+0x22b) [0x55a1c9d27e9b]", "(ReplicatedBackend::submit_transaction(hobject_t const&, object_stat_sum_t const&, eversion_t const&, std::unique_ptr<PGTransaction, std::default_delete<PGTransaction> >&&, eversion_t const&, eversion_t const&, std::vector<pg_log_entry_t, std::allocator<pg_log_entry_t> >&&, std::optional<pg_hit_set_history_t>&, Context*, unsigned long, osd_reqid_t, boost::intrusive_ptr<OpRequest>)+0x8ad) [0x55a1c9bbcfdd]", "(PrimaryLogPG::issue_repop(PrimaryLogPG::RepGather*, PrimaryLogPG::OpContext*)+0x38f) [0x55a1c99d1cbf]", "(PrimaryLogPG::simple_opc_submit(std::unique_ptr<PrimaryLogPG::OpContext, std::default_delete<PrimaryLogPG::OpContext> >)+0x57) [0x55a1c99d6777]", "(PrimaryLogPG::handle_watch_timeout(std::shared_ptr<Watch>)+0xb73) [0x55a1c99da883]", "/usr/bin/ceph-osd(+0x58794e) [0x55a1c992994e]", "(CommonSafeTimer<std::mutex>::timer_thread()+0x11a) [0x55a1c9e226aa]", "/usr/bin/ceph-osd(+0xa80eb1) [0x55a1c9e22eb1]", "/lib64/libc.so.6(+0x9f802) [0x7f64a636e802]", "/lib64/libc.so.6(+0x3f450) [0x7f64a630e450]" ], "ceph_version": "17.2.6", "crash_id": "2023-05-08T17:45:47.056675Z_a5759fe9-60c6-423a-88fc-57663f692bd3", "entity_name": "osd.98", "os_id": "almalinux", "os_name": "AlmaLinux", "os_version": "9.0 (Emerald Puma)", "os_version_id": "9.0", "process_name": "ceph-osd", "stack_sig": "b1a1c5bd45e23382497312202e16cfd7a62df018c6ebf9ded0f3b3ca3c1dfa66", "timestamp": "2023-05-08T17:45:47.056675Z", "utsname_hostname": "nrbphav4h", "utsname_machine": "x86_64", "utsname_release": "5.15.90lb9.01", "utsname_sysname": "Linux", "utsname_version": "#1 SMP Fri Jan 27 15:52:13 CET 2023" } I was trying to figure out why this particular 3 nodes could behave differently and found out from colleagues, that those 3 nodes were added to cluster lately with direct install of 17.2.5 (others were installed 15.2.16 and later upgraded) not sure whether this is related to our problem though.. I see very similar crash reported here:https://tracker.ceph.com/issues/56346 so I'm not reporting.. Do you think this might somehow be the cause of the problem? Anything else I should check in perf dumps or elsewhere?

Hmm... don't know yet. Could you please last 20K lines prior the crash from e.g two sample OSDs? And the crash isn't permanent, OSDs are able to start after the second(?) shot, aren't they?

...

with best regards nik

-- Igor Fedotov Ceph Lead Developer -- croit GmbH, Freseniusstr. 31h, 81247 Munich CEO: Martin Verges - VAT-ID: DE310638492 Com. register: Amtsgericht Munich HRB 231263 Web <https://croit.io/> | LinkedIn <http://linkedin.com/company/croit> | Youtube <https://www.youtube.com/channel/UCIJJSKVdcSLGLBtwSFx_epw> | Twitter <https://twitter.com/croit_io> Meet us at the SC22 Conference! Learn more <https://croit.io/croit-sc22> Technology Fast50 Award Winner by Deloitte <https://www2.deloitte.com/de/de/pages/technology-media-and-telecommunications/articles/fast-50-2022-germany-winners.html>! <https://www2.deloitte.com/de/de/pages/technology-media-and-telecommunications/articles/fast-50-2022-germany-winners.html>

Zakhar Kirpichenko

10:31 p.m.

Don't mean to hijack the thread, but I may be observing something similar with 16.2.12: OSD performance noticeably peaks after OSD restart and then gradually reduces over 10-14 days, while commit and apply latencies increase across the board. Non-default settings are: "bluestore_cache_size_hdd": { "default": "1073741824", "mon": "4294967296", "final": "4294967296" }, "bluestore_cache_size_ssd": { "default": "3221225472", "mon": "4294967296", "final": "4294967296" }, ... "osd_memory_cache_min": { "default": "134217728", "mon": "2147483648", "final": "2147483648" }, "osd_memory_target": { "default": "4294967296", "mon": "17179869184", "final": "17179869184" }, "osd_scrub_sleep": { "default": 0, "mon": 0.10000000000000001, "final": 0.10000000000000001 }, "rbd_balance_parent_reads": { "default": false, "mon": true, "final": true }, All other settings are default, the usage is rather simple Openstack / RBD. I also noticed that OSD cache usage doesn't increase over time (see my message "Ceph 16.2.12, bluestore cache doesn't seem to be used much" dated 26 April 2023, which received no comments), despite OSDs are being used rather heavily and there's plenty of host and OSD cache / target memory available. It may be worth checking if available memory is being used in a good way. /Z On Mon, 8 May 2023 at 22:35, Igor Fedotov <igor.fedotov(a)croit.io> wrote:

...

Hey Nikola, On 5/8/2023 10:13 PM, Nikola Ciprich wrote:

OK, starting collecting those for all OSDs.. I have hour samples of all OSDs perf dumps loaded in DB, so I can easily

examine,

sort, whatever..

> currently values for avgtime are around 0.0003 for subop_w_lat and

0.001-0.002

for op_w_lat

OK, so there is no visible trend on op_w_lat, still between 0.001 and

0.002

subop_w_lat seems to have increased since yesterday though! I see values

from

0.0004 to as high as 0.001 If some other perf data might be interesting, please let me know.. During OSD restarts, I noticed strange thing - restarts on first 6

machines

went smooth, but then on another 3, I saw rocksdb logs recovery on all

SSD

OSDs. but first didn't see any mention of daemon crash in ceph -s later, crash info appeared, but only about 3 daemons (in total, at least

of them crashed though) crash report was similar for all three OSDs: [root@nrbphav4a ~]# ceph crash info

2023-05-08T17:45:47.056675Z_a5759fe9-60c6-423a-88fc-57663f692bd3

{ "backtrace": [ "/lib64/libc.so.6(+0x54d90) [0x7f64a6323d90]", "(BlueStore::_txc_create(BlueStore::Collection*,

BlueStore::OpSequencer*, std::__cxx11::list<Context*, std::allocator<Context*> >*, boost::intrusive_ptr<TrackedOp>)+0x413) [0x55a1c9d07c43]",

"(BlueStore::queue_transactions(boost::intrusive_ptr<ObjectStore::CollectionImpl>&, std::vector<ceph::os::Transaction, std::allocator<ceph::os::Transaction>

&, boost::intrusive_ptr<TrackedOp>, ThreadPool::TPHandle*)+0x22b)

[0x55a1c9d27e9b]",

"(ReplicatedBackend::submit_transaction(hobject_t const&,

object_stat_sum_t const&, eversion_t const&, std::unique_ptr<PGTransaction, std::default_delete<PGTransaction> >&&, eversion_t const&, eversion_t const&, std::vector<pg_log_entry_t, std::allocator<pg_log_entry_t> >&&, std::optional<pg_hit_set_history_t>&, Context*, unsigned long, osd_reqid_t, boost::intrusive_ptr<OpRequest>)+0x8ad) [0x55a1c9bbcfdd]",

"(PrimaryLogPG::issue_repop(PrimaryLogPG::RepGather*,

PrimaryLogPG::OpContext*)+0x38f) [0x55a1c99d1cbf]",

"(PrimaryLogPG::simple_opc_submit(std::unique_ptr<PrimaryLogPG::OpContext, std::default_delete<PrimaryLogPG::OpContext> >)+0x57) [0x55a1c99d6777]",

"(PrimaryLogPG::handle_watch_timeout(std::shared_ptr<Watch>)+0xb73) [0x55a1c99da883]",

"/usr/bin/ceph-osd(+0x58794e) [0x55a1c992994e]", "(CommonSafeTimer<std::mutex>::timer_thread()+0x11a)

[0x55a1c9e226aa]",

"/usr/bin/ceph-osd(+0xa80eb1) [0x55a1c9e22eb1]", "/lib64/libc.so.6(+0x9f802) [0x7f64a636e802]", "/lib64/libc.so.6(+0x3f450) [0x7f64a630e450]" ], "ceph_version": "17.2.6", "crash_id":

"2023-05-08T17:45:47.056675Z_a5759fe9-60c6-423a-88fc-57663f692bd3",

"entity_name": "osd.98", "os_id": "almalinux", "os_name": "AlmaLinux", "os_version": "9.0 (Emerald Puma)", "os_version_id": "9.0", "process_name": "ceph-osd", "stack_sig":

"b1a1c5bd45e23382497312202e16cfd7a62df018c6ebf9ded0f3b3ca3c1dfa66", > "timestamp": "2023-05-08T17:45:47.056675Z", > "utsname_hostname": "nrbphav4h", > "utsname_machine": "x86_64", > "utsname_release": "5.15.90lb9.01", > "utsname_sysname": "Linux", > "utsname_version": "#1 SMP Fri Jan 27 15:52:13 CET 2023" > }

> I was trying to figure out why this particular 3 nodes could behave differently

and found out from colleagues, that those 3 nodes were added to cluster

lately

with direct install of 17.2.5 (others were installed 15.2.16 and later

upgraded)

> not sure whether this is related to our problem though..

> I see very similar crash reported here: https://tracker.ceph.com/issues/56346 > so I'm not reporting..

> Do you think this might somehow be the cause of the problem? Anything else I should

check in perf dumps or elsewhere?

Hmm... don't know yet. Could you please last 20K lines prior the crash from e.g two sample OSDs? And the crash isn't permanent, OSDs are able to start after the second(?) shot, aren't they? > with best regards

> nik

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Igor Fedotov

9 May 9 May

10:58 p.m.

...

OK, starting collecting those for all OSDs.. I have hour samples of all OSDs perf dumps loaded in DB, so I

can easily examine,

sort, whatever..

> currently values for avgtime are around 0.0003 for subop_w_lat

and 0.001-0.002

for op_w_lat

OK, so there is no visible trend on op_w_lat, still between

0.001 and 0.002

subop_w_lat seems to have increased since yesterday though! I

see values from

0.0004 to as high as 0.001 If some other perf data might be interesting, please let me know.. During OSD restarts, I noticed strange thing - restarts on first

6 machines

went smooth, but then on another 3, I saw rocksdb logs recovery

on all SSD

OSDs. but first didn't see any mention of daemon crash in ceph -s later, crash info appeared, but only about 3 daemons (in total,

at least 20

of them crashed though) crash report was similar for all three OSDs: [root@nrbphav4a ~]# ceph crash info

2023-05-08T17:45:47.056675Z_a5759fe9-60c6-423a-88fc-57663f692bd3

{ "backtrace": [ "/lib64/libc.so.6(+0x54d90) [0x7f64a6323d90]", "(BlueStore::_txc_create(BlueStore::Collection*,

BlueStore::OpSequencer*, std::__cxx11::list<Context*, std::allocator<Context*> >*, boost::intrusive_ptr<TrackedOp>)+0x413) [0x55a1c9d07c43]",

"(BlueStore::queue_transactions(boost::intrusive_ptr<ObjectStore::CollectionImpl>&, std::vector<ceph::os::Transaction, std::allocator<ceph::os::Transaction> >&, boost::intrusive_ptr<TrackedOp>, ThreadPool::TPHandle*)+0x22b) [0x55a1c9d27e9b]",

"(ReplicatedBackend::submit_transaction(hobject_t const&,

object_stat_sum_t const&, eversion_t const&, std::unique_ptr<PGTransaction, std::default_delete<PGTransaction>

&&, eversion_t const&, eversion_t const&,

std::vector<pg_log_entry_t, std::allocator<pg_log_entry_t> >&&, std::optional<pg_hit_set_history_t>&, Context*, unsigned long, osd_reqid_t, boost::intrusive_ptr<OpRequest>)+0x8ad) [0x55a1c9bbcfdd]",

"(PrimaryLogPG::issue_repop(PrimaryLogPG::RepGather*,

PrimaryLogPG::OpContext*)+0x38f) [0x55a1c99d1cbf]",

"(PrimaryLogPG::simple_opc_submit(std::unique_ptr<PrimaryLogPG::OpContext, std::default_delete<PrimaryLogPG::OpContext> >)+0x57) [0x55a1c99d6777]",

"(PrimaryLogPG::handle_watch_timeout(std::shared_ptr<Watch>)+0xb73) [0x55a1c99da883]",

"/usr/bin/ceph-osd(+0x58794e) [0x55a1c992994e]", "(CommonSafeTimer<std::mutex>::timer_thread()+0x11a)

[0x55a1c9e226aa]",

"/usr/bin/ceph-osd(+0xa80eb1) [0x55a1c9e22eb1]", "/lib64/libc.so.6(+0x9f802) [0x7f64a636e802]", "/lib64/libc.so.6(+0x3f450) [0x7f64a630e450]" ], "ceph_version": "17.2.6", "crash_id":

"2023-05-08T17:45:47.056675Z_a5759fe9-60c6-423a-88fc-57663f692bd3",

"entity_name": "osd.98", "os_id": "almalinux", "os_name": "AlmaLinux", "os_version": "9.0 (Emerald Puma)", "os_version_id": "9.0", "process_name": "ceph-osd", "stack_sig":

> I was trying to figure out why this particular 3 nodes could behave differently

and found out from colleagues, that those 3 nodes were added to

cluster lately

with direct install of 17.2.5 (others were installed 15.2.16 and

later upgraded)

> not sure whether this is related to our problem though..

> I see very similar crash reported here:https://tracker.ceph.com/issues/56346 > so I'm not reporting..

> Do you think this might somehow be the cause of the problem? Anything else I should

check in perf dumps or elsewhere?

> nik

Zakhar Kirpichenko

10 May 10 May

5:01 a.m.

...

Hi Zakhar, Let's leave questions regarding cache usage/tuning to a different topic for now. And concentrate on performance drop. Could you please do the same experiment I asked from Nikola once your cluster reaches "bad performance" state (Nikola, could you please use this improved scenario as well?): - collect perf counters for every OSD - reset perf counters for every OSD - leave the cluster running for 10 mins and collect perf counters again. - Then restart OSDs one-by-one starting with the worst OSD (in terms of subop_w_lat from the prev step). Wouldn't be sufficient to reset just a few OSDs before the cluster is back to normal? - if partial OSD restart is sufficient - please leave the remaining OSDs run as-is without reboot. - after the restart (no matter partial or complete one - the key thing it's should successful) reset all the perf counters and leave the cluster run for 30 mins and collect perf counters again. - wait 24 hours and collect the counters one more time - share all four counters snapshots. Thanks, Igor On 5/8/2023 11:31 PM, Zakhar Kirpichenko wrote: Don't mean to hijack the thread, but I may be observing something similar with 16.2.12: OSD performance noticeably peaks after OSD restart and then gradually reduces over 10-14 days, while commit and apply latencies increase across the board. Non-default settings are: "bluestore_cache_size_hdd": { "default": "1073741824", "mon": "4294967296", "final": "4294967296" }, "bluestore_cache_size_ssd": { "default": "3221225472", "mon": "4294967296", "final": "4294967296" }, ... "osd_memory_cache_min": { "default": "134217728", "mon": "2147483648", "final": "2147483648" }, "osd_memory_target": { "default": "4294967296", "mon": "17179869184", "final": "17179869184" }, "osd_scrub_sleep": { "default": 0, "mon": 0.10000000000000001, "final": 0.10000000000000001 }, "rbd_balance_parent_reads": { "default": false, "mon": true, "final": true }, All other settings are default, the usage is rather simple Openstack / RBD. I also noticed that OSD cache usage doesn't increase over time (see my message "Ceph 16.2.12, bluestore cache doesn't seem to be used much" dated 26 April 2023, which received no comments), despite OSDs are being used rather heavily and there's plenty of host and OSD cache / target memory available. It may be worth checking if available memory is being used in a good way. /Z On Mon, 8 May 2023 at 22:35, Igor Fedotov <igor.fedotov(a)croit.io> wrote:

Hey Nikola, On 5/8/2023 10:13 PM, Nikola Ciprich wrote:

OK, starting collecting those for all OSDs.. I have hour samples of all OSDs perf dumps loaded in DB, so I can

easily examine,

sort, whatever..

> currently values for avgtime are around 0.0003 for subop_w_lat and

0.001-0.002

for op_w_lat

OK, so there is no visible trend on op_w_lat, still between 0.001 and

0.002

subop_w_lat seems to have increased since yesterday though! I see

values from

0.0004 to as high as 0.001 If some other perf data might be interesting, please let me know.. During OSD restarts, I noticed strange thing - restarts on first 6

machines

went smooth, but then on another 3, I saw rocksdb logs recovery on all

SSD

OSDs. but first didn't see any mention of daemon crash in ceph -s later, crash info appeared, but only about 3 daemons (in total, at

least 20

of them crashed though) crash report was similar for all three OSDs: [root@nrbphav4a ~]# ceph crash info

2023-05-08T17:45:47.056675Z_a5759fe9-60c6-423a-88fc-57663f692bd3

{ "backtrace": [ "/lib64/libc.so.6(+0x54d90) [0x7f64a6323d90]", "(BlueStore::_txc_create(BlueStore::Collection*,

BlueStore::OpSequencer*, std::__cxx11::list<Context*, std::allocator<Context*> >*, boost::intrusive_ptr<TrackedOp>)+0x413) [0x55a1c9d07c43]",

"(BlueStore::queue_transactions(boost::intrusive_ptr<ObjectStore::CollectionImpl>&, std::vector<ceph::os::Transaction, std::allocator<ceph::os::Transaction>

&, boost::intrusive_ptr<TrackedOp>, ThreadPool::TPHandle*)+0x22b)

[0x55a1c9d27e9b]",

"(ReplicatedBackend::submit_transaction(hobject_t const&,

"(PrimaryLogPG::issue_repop(PrimaryLogPG::RepGather*,

PrimaryLogPG::OpContext*)+0x38f) [0x55a1c99d1cbf]",

"(PrimaryLogPG::simple_opc_submit(std::unique_ptr<PrimaryLogPG::OpContext, std::default_delete<PrimaryLogPG::OpContext> >)+0x57) [0x55a1c99d6777]",

"(PrimaryLogPG::handle_watch_timeout(std::shared_ptr<Watch>)+0xb73) [0x55a1c99da883]",

"/usr/bin/ceph-osd(+0x58794e) [0x55a1c992994e]", "(CommonSafeTimer<std::mutex>::timer_thread()+0x11a)

[0x55a1c9e226aa]",

"/usr/bin/ceph-osd(+0xa80eb1) [0x55a1c9e22eb1]", "/lib64/libc.so.6(+0x9f802) [0x7f64a636e802]", "/lib64/libc.so.6(+0x3f450) [0x7f64a630e450]" ], "ceph_version": "17.2.6", "crash_id":

"2023-05-08T17:45:47.056675Z_a5759fe9-60c6-423a-88fc-57663f692bd3",

"entity_name": "osd.98", "os_id": "almalinux", "os_name": "AlmaLinux", "os_version": "9.0 (Emerald Puma)", "os_version_id": "9.0", "process_name": "ceph-osd", "stack_sig":

> I was trying to figure out why this particular 3 nodes could behave differently

and found out from colleagues, that those 3 nodes were added to cluster

lately

with direct install of 17.2.5 (others were installed 15.2.16 and later

upgraded)

> not sure whether this is related to our problem though..

> I see very similar crash reported here: https://tracker.ceph.com/issues/56346 > so I'm not reporting..

> Do you think this might somehow be the cause of the problem? Anything else I should

check in perf dumps or elsewhere?

> nik

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-- Igor Fedotov Ceph Lead Developer -- croit GmbH, Freseniusstr. 31h, 81247 Munich CEO: Martin Verges - VAT-ID: DE310638492 Com. register: Amtsgericht Munich HRB 231263 Web <https://croit.io/> | LinkedIn <http://linkedin.com/company/croit> | Youtube <https://www.youtube.com/channel/UCIJJSKVdcSLGLBtwSFx_epw> | Twitter <https://twitter.com/croit_io> Meet us at the SC22 Conference! Learn more <https://croit.io/croit-sc22> Technology Fast50 Award Winner by Deloitte <https://www2.deloitte.com/de/de/pages/technology-media-and-telecommunications/articles/fast-50-2022-germany-winners.html> ! <https://www2.deloitte.com/de/de/pages/technology-media-and-telecommunications/articles/fast-50-2022-germany-winners.html>

Igor Fedotov

9:15 a.m.

Hey Zakhar, You do need to restart OSDs to bring performance back to normal anyway, don't you? So yeah, we're not aware of better way so far - all the information I have is from you and Nikola. And you both tell us about the need for restart. Apparently there is no need to restart every OSD but "degraded/slow" ones only. We actually need to verify that. So please indicate the slowest OSDs (in terms of subop_w_lat) and do restart for them first. Hopefully just a fraction of your OSDs would require this. Thanks, Igor On 5/10/2023 6:01 AM, Zakhar Kirpichenko wrote:

...

Thank you, Igor. I will try to see how to collect the perf values. Not sure about restarting all OSDs as it's a production cluster, is there a less invasive way? /Z On Tue, 9 May 2023 at 23:58, Igor Fedotov <igor.fedotov(a)croit.io> wrote: Hi Zakhar, Let's leave questions regarding cache usage/tuning to a different topic for now. And concentrate on performance drop. Could you please do the same experiment I asked from Nikola once your cluster reaches "bad performance" state (Nikola, could you please use this improved scenario as well?): - collect perf counters for every OSD - reset perf counters for every OSD - leave the cluster running for 10 mins and collect perf counters again. - Then restart OSDs one-by-one starting with the worst OSD (in terms of subop_w_lat from the prev step). Wouldn't be sufficient to reset just a few OSDs before the cluster is back to normal? - if partial OSD restart is sufficient - please leave the remaining OSDs run as-is without reboot. - after the restart (no matter partial or complete one - the key thing it's should successful) reset all the perf counters and leave the cluster run for 30 mins and collect perf counters again. - wait 24 hours and collect the counters one more time - share all four counters snapshots. Thanks, Igor On 5/8/2023 11:31 PM, Zakhar Kirpichenko wrote:

OK, starting collecting those for all OSDs.. I have hour samples of all OSDs perf dumps loaded in DB, so

I can easily examine,

sort, whatever..

> currently values for avgtime are around 0.0003 for

subop_w_lat and 0.001-0.002

for op_w_lat

OK, so there is no visible trend on op_w_lat, still between

0.001 and 0.002

subop_w_lat seems to have increased since yesterday though!

I see values from

0.0004 to as high as 0.001 If some other perf data might be interesting, please let me

know..

During OSD restarts, I noticed strange thing - restarts on

first 6 machines

went smooth, but then on another 3, I saw rocksdb logs

recovery on all SSD

OSDs. but first didn't see any mention of daemon crash in

ceph -s

later, crash info appeared, but only about 3 daemons (in

total, at least 20

of them crashed though) crash report was similar for all three OSDs: [root@nrbphav4a ~]# ceph crash info

2023-05-08T17:45:47.056675Z_a5759fe9-60c6-423a-88fc-57663f692bd3

{ "backtrace": [ "/lib64/libc.so.6(+0x54d90) [0x7f64a6323d90]", "(BlueStore::_txc_create(BlueStore::Collection*,

BlueStore::OpSequencer*, std::__cxx11::list<Context*, std::allocator<Context*> >*, boost::intrusive_ptr<TrackedOp>)+0x413) [0x55a1c9d07c43]",

"(ReplicatedBackend::submit_transaction(hobject_t const&,

"(PrimaryLogPG::issue_repop(PrimaryLogPG::RepGather*,

PrimaryLogPG::OpContext*)+0x38f) [0x55a1c99d1cbf]",

"(PrimaryLogPG::simple_opc_submit(std::unique_ptr<PrimaryLogPG::OpContext, std::default_delete<PrimaryLogPG::OpContext> >)+0x57) [0x55a1c99d6777]",

"(PrimaryLogPG::handle_watch_timeout(std::shared_ptr<Watch>)+0xb73) [0x55a1c99da883]",

"/usr/bin/ceph-osd(+0x58794e) [0x55a1c992994e]", "(CommonSafeTimer<std::mutex>::timer_thread()+0x11a)

[0x55a1c9e226aa]",

"/usr/bin/ceph-osd(+0xa80eb1) [0x55a1c9e22eb1]", "/lib64/libc.so.6(+0x9f802) [0x7f64a636e802]", "/lib64/libc.so.6(+0x3f450) [0x7f64a630e450]" ], "ceph_version": "17.2.6", "crash_id":

"2023-05-08T17:45:47.056675Z_a5759fe9-60c6-423a-88fc-57663f692bd3",

"entity_name": "osd.98", "os_id": "almalinux", "os_name": "AlmaLinux", "os_version": "9.0 (Emerald Puma)", "os_version_id": "9.0", "process_name": "ceph-osd", "stack_sig":

> I was trying to figure out why this particular 3 nodes could behave differently

and found out from colleagues, that those 3 nodes were

added to cluster lately

with direct install of 17.2.5 (others were installed

15.2.16 and later upgraded)

> not sure whether this is related to our problem though..

> I see very similar crash reported here:https://tracker.ceph.com/issues/56346 > so I'm not reporting..

> Do you think this might somehow be the cause of the problem? Anything else I should

check in perf dumps or elsewhere?

> nik

Nikola Ciprich

7:36 a.m.

Hello Igor,

...

You didn't reset the counters every hour, do you? So having average subop_w_latency growing that way means the current values were much higher than before.

bummer, I didn't.. I've updated gather script to reset stats, wait 10m and then gather perf data, each hour. It's running since yesterday, so now we'll have to wait about one week for the problem to appear again..

...

Curious if subop latencies were growing for every OSD or just a subset (may be even just a single one) of them?

since I only have long time averaga, it's not easy to say, but based on what we have: only two OSDs avg got sub_w_lat > 0.0006. no clear relation between them 19 OSDs got avg sub_w_lat > 0.0005 - this is more interesting - 15 out of them are on those later installed nodes (note that those nodes have almost no VMs running so they are much less used!) 4 are on other nodes. but also note, that not all of OSDs on suspicious nodes are over the threshold, it's 6, 6 and 3 out of 7 OSDs on the node. but still it's strange..

...

Next time you reach the bad state please do the following if possible: - reset perf counters for every OSD - leave the cluster running for 10 mins and collect perf counters again. - Then start restarting OSD one-by-one starting with the worst OSD (in terms of subop_w_lat from the prev step). Wouldn't be sufficient to reset just a few OSDs before the cluster is back to normal?

will do once it slows down again.

...

I see very similar crash reported here:https://tracker.ceph.com/issues/56346 so I'm not reporting.. Do you think this might somehow be the cause of the problem? Anything else I should check in perf dumps or elsewhere?

Hmm... don't know yet. Could you please last 20K lines prior the crash from e.g two sample OSDs?

https://storage.linuxbox.cz/index.php/s/o5bMaGMiZQxWadi

...

And the crash isn't permanent, OSDs are able to start after the second(?) shot, aren't they?

yes, actually they start after issuing systemctl ceph-osd@xx restart, it just takes long time performing log recovery.. If I can provide more info, please let me know BR nik -- ------------------------------------- Ing. Nikola CIPRICH LinuxBox.cz, s.r.o. 28.rijna 168, 709 00 Ostrava tel.: +420 591 166 214 fax: +420 596 621 273 mobil: +420 777 093 799 www.linuxbox.cz mobil servis: +420 737 238 656 email servis: servis(a)linuxbox.cz -------------------------------------

Nikola Ciprich

23 May 23 May

7:17 p.m.

Hello Igor, just reporting, that since last restart (after reverting changed values to their defaults) the performance hasn't decreased (and it's been over two weeks now). So either it helped after all, or the drop is caused by something else I'll yet have to figure out.. we've automated the test so once the performance drops beyond threshold, I'll know it and investigate further (and report) cheers with regards nik On Wed, May 10, 2023 at 07:36:06AM +0200, Nikola Ciprich wrote:

...

Hello Igor,

You didn't reset the counters every hour, do you? So having average subop_w_latency growing that way means the current values were much higher than before.

Curious if subop latencies were growing for every OSD or just a subset (may be even just a single one) of them?

will do once it slows down again.

Hmm... don't know yet. Could you please last 20K lines prior the crash from e.g two sample OSDs?

https://storage.linuxbox.cz/index.php/s/o5bMaGMiZQxWadi

And the crash isn't permanent, OSDs are able to start after the second(?) shot, aren't they?

Mark Nelson

10:26 p.m.

Hi Nikola, Just to be clear, these were the settings that you changed back to the defaults?

...

Non-default settings are: "bluestore_cache_size_hdd": { "default": "1073741824", "mon": "4294967296", "final": "4294967296" }, "bluestore_cache_size_ssd": { "default": "3221225472", "mon": "4294967296", "final": "4294967296" }, ... "osd_memory_cache_min": { "default": "134217728", "mon": "2147483648", "final": "2147483648" }, "osd_memory_target": { "default": "4294967296", "mon": "17179869184", "final": "17179869184" }, "osd_scrub_sleep": { "default": 0, "mon": 0.10000000000000001, "final": 0.10000000000000001 }, "rbd_balance_parent_reads": { "default": false, "mon": true, "final": true },

Thanks, Mark On 5/23/23 12:17, Nikola Ciprich wrote:

...

Hello Igor,

You didn't reset the counters every hour, do you? So having average subop_w_latency growing that way means the current values were much higher than before.

Curious if subop latencies were growing for every OSD or just a subset (may be even just a single one) of them?

will do once it slows down again.

Hmm... don't know yet. Could you please last 20K lines prior the crash from e.g two sample OSDs?

https://storage.linuxbox.cz/index.php/s/o5bMaGMiZQxWadi

And the crash isn't permanent, OSDs are able to start after the second(?) shot, aren't they?

-- Best Regards, Mark Nelson Head of R&D (USA) Clyso GmbH p: +49 89 21552391 12 a: Loristraße 8 | 80335 München | Germany w: https://clyso.com | e: mark.nelson(a)clyso.com We are hiring: https://www.clyso.com/jobs/

stachecki.tyler＠gmail.com

22 Jul 22 Jul

6:25 p.m.

Mark, I ran into something similar to this recently while testing Quincy... I believe I see what happened here. Based on the users information, the following non-default option was in use: ceph config set osd bluestore_rocksdb_options compression=kNoCompression,max_write_buffer_number=32,min_write_buffer_number_to_merge=2,recycle_log_file_num=32,compaction_style=kCompactionStyleLevel,write_buffer_size=67108864,target_file_size_base=67108864,max_background_compactions=31,level0_file_num_compaction_trigger=8,level0_slowdown_writes_trigger=32,level0_stop_writes_trigger=64,max_bytes_for_level_base=536870912,compaction_threads=32,max_bytes_for_level_multiplier=8,flusher_threads=8,compaction_readahead_size=2MB This overriden option does not have the cap for WAL sizing, which is needed since the column family sharding was added to RocksDB: https://github.com/ceph/ceph/pull/35277 Without that option specific as part of bluestore_rocksdb_options, Quincy will use ~100GiB WALs. Everything works great until the WALs fill, and then the cluster begins caving in on itself progressively. Cheers, Tyler

Igor Fedotov

2 May 2 May

4:50 p.m.

On 5/2/2023 11:32 AM, Nikola Ciprich wrote:

...

I've updated cluster to 17.2.6 some time ago, but the problem persists. This is especially annoying in connection with https://tracker.ceph.com/issues/56896 as restarting OSDs is quite painfull when half of them crash.. with best regards

Feel free to set osd_fast_shutdown_timeout to zero to workaround the above. IMO this assertion is a nonsence and I don't see any usage of this timeout parameter other than just throw an assertion. -- Igor Fedotov Ceph Lead Developer Looking for help with your Ceph cluster? Contact us at https://croit.io croit GmbH, Freseniusstr. 31h, 81247 Munich CEO: Martin Verges - VAT-ID: DE310638492 Com. register: Amtsgericht Munich HRB 231263 Web: https://croit.io | YouTube: https://goo.gl/PGE1Bx

Gregory Farnum

5 p.m.

On Tue, May 2, 2023 at 7:54 AM Igor Fedotov <igor.fedotov(a)croit.io> wrote:

...

On 5/2/2023 11:32 AM, Nikola Ciprich wrote:

Feel free to set osd_fast_shutdown_timeout to zero to workaround the above. IMO this assertion is a nonsence and I don't see any usage of this timeout parameter other than just throw an assertion.

This was added by Gabi in https://github.com/ceph/ceph/commit/9b2a64a5f6ea743b2a4f4c2dbd703248d88b2a96; presumably he has insight. I wonder if it's just a debug config so we can see slow shutdowns in our test runs? In which case it should certainly default to 0 and get set for those test suites. -Greg

...

-- Igor Fedotov Ceph Lead Developer Looking for help with your Ceph cluster? Contact us at https://croit.io croit GmbH, Freseniusstr. 31h, 81247 Munich CEO: Martin Verges - VAT-ID: DE310638492 Com. register: Amtsgericht Munich HRB 231263 Web: https://croit.io | YouTube: https://goo.gl/PGE1Bx _______________________________________________ ceph-users mailing list -- ceph-users(a)ceph.io To unsubscribe send an email to ceph-users-leave(a)ceph.io

Gabriel Benhanokh

17 Jul 17 Jul

2:02 p.m.

Greg, You are correct - the timeout was used during debug to make sure the fast shutdown is indeed fast, but even if it completed after that timeout everything should be perfectly fine. The timeout was set to 15 seconds which is more than enough to complete shutdown on a valid system (in reality we only need 1-2 seconds). We can simply remove the assert (or maybe increase the timeout from 15s to 30s), but that won't explain what is the we did so long during shutdown. I suggest analyzing the shutdown process to find the root cause (which might be related to the overall system slowdown). The OP describes a 10x slowdown in writes which might have been translated to a 10X time during fast-shutdown from 2 seconds to 20 seconds (and so exceeding the 15 second timeout). Other possibility is that the system was running with extremely high log level which is something I can address in the code by checking the log-level before asserting

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16 comments

7 participants

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participants (7)

Gabriel Benhanokh
Gregory Farnum
Igor Fedotov
Mark Nelson
Nikola Ciprich
stachecki.tyler＠gmail.com
Zakhar Kirpichenko