March 2021 - ceph-users - lists.ceph.io

Small RGW objects and RADOS 64KB minimun size

by Loïc Dachary

Bonjour, Reading Karan's blog post about benchmarking the insertion of billions objects to Ceph via S3 / RGW[0] from last year, it reads: > we decided to lower bluestore_min_alloc_size_hdd to 18KB and re-test. As represented in chart-5, the object creation rate found to be notably reduced after lowering the bluestore_min_alloc_size_hdd parameter from 64KB (default) to 18KB. As such, for objects larger than the bluestore_min_alloc_size_hdd , the default values seems to be optimal, smaller objects further require more investigation if you intended to reduce bluestore_min_alloc_size_hdd parameter. There also is a mail thread dated 2018 on this topic as well, with the same conclusion although using RADOS directly and not RGW[3]. I read the RGW data layout page in the documentation[1] and concluded that by default every object inserted with S3 / RGW will indeed use at least 64kb. A pull request from last year[2] seems to confirm it and also suggests modifying bluestore_min_alloc_size_hdd has adverse side effects. That being said, I'm curious to know if people developed strategies to cope with this overhead. Someone mentioned packing objects together client side to make them larger. But maybe there are simpler ways to do the same? Cheers [0] https://www.redhat.com/en/blog/scaling-ceph-billion-objects-and-beyond [1] https://docs.ceph.com/en/latest/radosgw/layout/ [2] https://github.com/ceph/ceph/pull/32809 [3] https://www.spinics.net/lists/ceph-users/msg45755.html -- Loïc Dachary, Artisan Logiciel Libre

6 months, 1 week

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cephadm cluster move /var/lib/docker to separate device fails

by Karsten Nielsen

Hi, I have setup a ceph cluster with cephadm with docker backend. I want to move /var/lib/docker to a separate device to get better performance and less load on the OS device. I tried that by stopping docker copy the content of /var/lib/docker to the new device and mount the new device to /var/lib/docker. The other containers started as expected and continues to work and run as expected. But the ceph containers seems to be broken. I am not able to get them back in working state. I have tried to remove the host with `ceph orch host rm itcnchn-bb4067` and readd it but no effect. The strange thing is that 2 of 4 containers comes up as expected. ceph orch ps itcnchn-bb4067 NAME HOST STATUS REFRESHED AGE VERSION IMAGE NAME IMAGE ID CONTAINER ID crash.itcnchn-bb4067 itcnchn-bb4067 running (18h) 10m ago 4w 15.2.7 docker.io/ceph/ceph:v15 2bc420ddb175 2af28c4571cf mds.cephfs.itcnchn-bb4067.qzoshl itcnchn-bb4067 error 10m ago 4w <unknown> docker.io/ceph/ceph:v15 <unknown> <unknown> mon.itcnchn-bb4067 itcnchn-bb4067 error 10m ago 18h <unknown> docker.io/ceph/ceph:v15 <unknown> <unknown> rgw.ikea.dc9-1.itcnchn-bb4067.gtqedc itcnchn-bb4067 running (18h) 10m ago 4w 15.2.7 docker.io/ceph/ceph:v15 2bc420ddb175 00d000aec32b Docker logs from the active manager does not say much about what is wrong debug 2021-01-05T09:57:52.537+0000 7fdb69691700 0 log_channel(cephadm) log [INF] : Reconfiguring mds.cephfs.itcnchn-bb4067.qzoshl (unknown last config time)... debug 2021-01-05T09:57:52.541+0000 7fdb69691700 0 log_channel(cephadm) log [INF] : Reconfiguring daemon mds.cephfs.itcnchn-bb4067.qzoshl on itcnchn-bb4067 debug 2021-01-05T09:57:52.973+0000 7fdb64e88700 0 log_channel(cluster) log [DBG] : pgmap v347: 241 pgs: 241 active+clean; 18 GiB data, 50 GiB used, 52 TiB / 52 TiB avail; 18 KiB/s rd, 78 KiB/s wr, 24 op/s debug 2021-01-05T09:57:53.085+0000 7fdb69691700 0 log_channel(cephadm) log [INF] : Reconfiguring mon.itcnchn-bb4067 (unknown last config time)... debug 2021-01-05T09:57:53.085+0000 7fdb69691700 0 log_channel(cephadm) log [INF] : Reconfiguring daemon mon.itcnchn-bb4067 on itcnchn-bb4067 debug 2021-01-05T09:57:53.625+0000 7fdb69691700 0 log_channel(cephadm) log [INF] : Reconfiguring rgw.ikea.dc9-1.itcnchn-bb4067.gtqedc (unknown last config time)... debug 2021-01-05T09:57:53.629+0000 7fdb69691700 0 log_channel(cephadm) log [INF] : Reconfiguring daemon rgw.ikea.dc9-1.itcnchn-bb4067.gtqedc on itcnchn-bb4067 debug 2021-01-05T09:57:54.141+0000 7fdb69691700 0 log_channel(cephadm) log [INF] : Reconfiguring crash.itcnchn-bb4067 (unknown last config time)... debug 2021-01-05T09:57:54.141+0000 7fdb69691700 0 log_channel(cephadm) log [INF] : Reconfiguring daemon crash.itcnchn-bb4067 on itcnchn-bb4067 - Karsten

8 months, 2 weeks

2
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kernel client osdc ops stuck and mds slow reqs

by Dan van der Ster

Hi all, We are quite regularly (a couple times per week) seeing: HEALTH_WARN 1 clients failing to respond to capability release; 1 MDSs report slow requests MDS_CLIENT_LATE_RELEASE 1 clients failing to respond to capability release mdshpc-be143(mds.0): Client hpc-be028.cern.ch: failing to respond to capability release client_id: 52919162 MDS_SLOW_REQUEST 1 MDSs report slow requests mdshpc-be143(mds.0): 1 slow requests are blocked > 30 secs Which is being caused by osdc ops stuck in a kernel client, e.g.: 10:57:18 root hpc-be028 /root → cat /sys/kernel/debug/ceph/4da6fd06-b069-49af-901f-c9513baabdbd.client52919162/osdc REQUESTS 9 homeless 0 46559317 osd243 3.ee6ffcdb 3.cdb [243,501,92]/243 [243,501,92]/243 e678697 fsvolumens_355f485c-6319-4ffe-acd6-94a07f2a14b4/10003f09a01.00000057 0x400014 1 read 46559322 osd243 3.ee6ffcdb 3.cdb [243,501,92]/243 [243,501,92]/243 e678697 fsvolumens_355f485c-6319-4ffe-acd6-94a07f2a14b4/10003f09a01.00000057 0x400014 1 read 46559323 osd243 3.969cc573 3.573 [243,330,226]/243 [243,330,226]/243 e678697 fsvolumens_355f485c-6319-4ffe-acd6-94a07f2a14b4/10003f09a56.00000056 0x400014 1 read 46559341 osd243 3.969cc573 3.573 [243,330,226]/243 [243,330,226]/243 e678697 fsvolumens_355f485c-6319-4ffe-acd6-94a07f2a14b4/10003f09a56.00000056 0x400014 1 read 46559342 osd243 3.969cc573 3.573 [243,330,226]/243 [243,330,226]/243 e678697 fsvolumens_355f485c-6319-4ffe-acd6-94a07f2a14b4/10003f09a56.00000056 0x400014 1 read 46559345 osd243 3.969cc573 3.573 [243,330,226]/243 [243,330,226]/243 e678697 fsvolumens_355f485c-6319-4ffe-acd6-94a07f2a14b4/10003f09a56.00000056 0x400014 1 read 46559621 osd243 3.6313e8ef 3.8ef [243,330,521]/243 [243,330,521]/243 e678697 fsvolumens_355f485c-6319-4ffe-acd6-94a07f2a14b4/10003f09a45.0000007a 0x400014 1 read 46559629 osd243 3.b280c852 3.852 [243,113,539]/243 [243,113,539]/243 e678697 fsvolumens_355f485c-6319-4ffe-acd6-94a07f2a14b4/10003f09a3a.0000007f 0x400014 1 read 46559928 osd243 3.1ee7bab4 3.ab4 [243,332,94]/243 [243,332,94]/243 e678697 fsvolumens_355f485c-6319-4ffe-acd6-94a07f2a14b4/10003f099ff.0000073f 0x400024 1 write LINGER REQUESTS BACKOFFS We can unblock those requests by doing `ceph osd down osd.243` (or restarting osd.243). This is ceph v14.2.6 and the client kernel is el7 3.10.0-957.27.2.el7.x86_64. Are there a better way to debug this? Best Regards, Dan

9 months, 3 weeks

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cephfs forward scrubbing docs

by Dan van der Ster

Hi, Today while debugging something we had a few questions that might lead to improving the cephfs forward scrub docs: https://docs.ceph.com/en/latest/cephfs/scrub/ tldr: 1. Should we document which sorts of issues that the forward scrub is able to fix? 2. Can we make it more visible (in docs) that scrubbing is not supported with multi-mds? 3. Isn't the new `ceph -s` scrub task status misleading with multi-mds? Details here: 1) We found a CephFS directory with a number of zero sized files: # ls -l ... -rw-r--r-- 1 1001890000 1001890000 0 Nov 3 11:58 upload_fc501199e3e7abe6b574101cf34aeefb.png -rw-r--r-- 1 1001890000 1001890000 0 Nov 3 12:23 upload_fce4f55348185fefa0abdd8d11095ba8.gif -rw-r--r-- 1 1001890000 1001890000 0 Nov 3 11:54 upload_fd95b8358851f0dac22fb775046a6163.png ... The user claims that those files were non-zero sized last week. The sequence of zero sized files includes *all* files written between Nov 2 and 9. The user claims that his client was running out of memory, but this is now fixed. So I suspect that his ceph client (kernel 3.10.0-1127.19.1.el7.x86_64) was not behaving well. Anyway, I noticed that even though the dentries list 0 bytes, the underlying rados objects have data, and the data looks good. E.g. # rados get -p cephfs_data 200212e68b5.00000000 --namespace=xxx 200212e68b5.00000000 # file 200212e68b5.00000000 200212e68b5.00000000: PNG image data, 960 x 815, 8-bit/color RGBA, non-interlaced So I managed to recover the files doing something like this (using an input file mapping inode to filename) [see PS 0]. But I'm wondering if a forward scrub is able to fix this sort of problem directly? Should we document which sorts of issues that the forward scrub is able to fix? I anyway tried to scrub it, which led to: # ceph tell mds.cephflax-mds-xxx scrub start /volumes/_nogroup/xxx recursive repair Scrub is not currently supported for multiple active MDS. Please reduce max_mds to 1 and then scrub. So ... 2) Shouldn't we update the doc to mention loud and clear that scrub is not currently supported for multiple active MDS? 3) I was somehow surprised by this, because I had thought that the new `ceph -s` multi-mds scrub status implied that multi-mds scrubbing was now working: task status: scrub status: mds.x: idle mds.y: idle mds.z: idle Is it worth reporting this task status for cephfs if we can't even scrub them? Thanks!! Dan [0] mkdir -p recovered while read -r a b; do for i in {0..9} do echo "rados stat --cluster=flax --pool=cephfs_data --namespace=xxx" $(printf "%x" $a).0000000$i "&&" "rados get --cluster=flax --pool=cephfs_data --namespace=xxx" $(printf "%x" $a).0000000$i $(printf "%x" $a).0000000$i done echo cat $(printf "%x" $a).* ">" $(printf "%x" $a) echo mv $(printf "%x" $a) recovered/$b done < inones_fnames.txt

2 years, 5 months

2
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does ceph rgw has any option to limit bandwidth

by Zhenshi Zhou

Hi, Is there any option of rados gateway that limit bandwidth?

2 years, 6 months

5
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Recommendations on problem with PG

by Gabriel Medve

Hi, We have a problem with a PG that was inconsistent, currently the PG in our cluster have 3 copies. It was not possible for us to repair this pg with "ceph pg repair" (This PG is in osd 14,1,2) so we deleted some of the copies of osd 14 with the following command. ceph-objectstore-tool --data-path /var/lib/ceph/osd.14/ --pgid 22.f --op remove --force This caused an automatic attempt to create the missing copy entering the backfilling state, but when doing this it crashed osd 1 and 2 and threw the IOPS to 0, freezing the cluster. Is there any way to remove this entire pg or try to recreate the missing copy or ignore it completely? It causes instability in the cluster. Thank you, I await comments -- Untitled Document ------------------------------------------------------------------------ Gabriel I. Medve

2 years, 6 months

2
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ceph-ansible in Pacific and beyond?

by Matthew Vernon

Hi, I caught up with Sage's talk on what to expect in Pacific ( https://www.youtube.com/watch?v=PVtn53MbxTc ) and there was no mention of ceph-ansible at all. Is it going to continue to be supported? We use it (and uncontainerised packages) for all our clusters, so I'd be a bit alarmed if it was going to go away... Regards, Matthew -- The Wellcome Sanger Institute is operated by Genome Research Limited, a charity registered in England with number 1021457 and a company registered in England with number 2742969, whose registered office is 215 Euston Road, London, NW1 2BE.

2 years, 6 months

17
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RGW: Multiple Site does not sync olds data

by 特木勒

Hi all: ceph version: 15.2.7 (88e41c6c49beb18add4fdb6b4326ca466d931db8) I have a strange question, I just create a multiple site for Ceph cluster. But I notice the old data of source cluster is not synced. Only new data will be synced into second zone cluster. Is there anything I need to do to enable full sync for bucket or this is a bug? Thanks

2 years, 6 months

3
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Zabbix module Octopus 15.2.3

by Gert Wieberdink

Trying to configure Zabbix module in Octopus 15.2.3. CentOS 8.1 environment. Installed zabbix40-agent for CentOS 8.1 (from epel repository). This will also install zabbix_sender. After enabling the Zabbix module in Ceph, I configured my Zabbix host and Zabbix identifier. # ceph zabbix config-set zabbix_host <zabbix-fqdn> # ceph zabbix config-set zabbix_identifier <ident> # ceph zabbix config-show Error EINVAL: Traceback (most recent call last): File "/usr/share/ceph/mgr/mgr_module.py", line 1153, in _handle_command return self.handle_command(inbuf, cmd) File "/usr/share/ceph/mgr/zabbix/module.py", line 407, in handle_command return 0, json.dumps(self.config, index=4, sort_keys=True), '' File "/lib64/python3.6/json/__init__.py", line 238, in dumps **kw).encode(obj) TypeError: __init__() got an unexpected keyword argument 'index' # ceph -v ceph version 15.2.3 (d289bbdec69ed7c1f516e0a093594580a76b78d0) octopus (stable) # ceph health detail HEALTH_OK Anyone found a solution? rgds, -gw

2 years, 7 months

5
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OSD id 241 != my id 248: conversion from "ceph-disk" to "ceph-volume simple" destroys OSDs

by Frank Schilder

Hi all, this is a follow-up on "reboot breaks OSDs converted from ceph-disk to ceph-volume simple". I converted a number of ceph-disk OSDs to ceph-volume using "simple scan" and "simple activate". Somewhere along the way, the OSDs meta-data gets rigged and the prominent symptom is that the symlink block is changes from a part-uuid target to an unstable device name target like: before conversion: block -> /dev/disk/by-partuuid/9123be91-7620-495a-a9b7-cc85b1de24b7 after conversion: block -> /dev/sdj2 This is a huge problem as the "after conversion" device names are unstable. I have now a cluster that I cannot reboot servers on due to this problem. OSDs randomly re-assigned devices will refuse to start with: 2021-03-02 15:56:21.709 7fb7c2549b80 -1 OSD id 241 != my id 248 Please help me with getting out of this mess. Thanks and best regards, ================= Frank Schilder AIT Risø Campus Bygning 109, rum S14

2 years, 7 months

2
7
0 0

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ceph-users March 2021