Do you think 4GB RAM for two OSD's is low, even with 1 OSD and 4GB memory i
encounter OOM during recovery.
This is just a test setup to try with ceph.
I am planning to use ceph in 36 drive system with Xeon e5v2 proc, 32 GB
RAM, 10Gb nic.
So, i am trying to optimize on memory usage on test setup which can be
latter used if using ceph.
On Sun 22 Sep, 2019, 12:02 PM Ashley Merrick, <singapore(a)amerrick.co.uk>
wrote:
I'm not aware of any memory settings that control
rebuild memory usage.
You are running very under on RAM, have you tried adding more swap or
adjusting /proc/sys/vm/*swappiness*
---- On Fri, 20 Sep 2019 20:41:09 +0800 *Amudhan P <amudhan83(a)gmail.com
<amudhan83(a)gmail.com>>* wrote ----
Hi,
I am using ceph mimic in a small test setup using the below configuration.
OS: ubuntu 18.04
1 node running (mon,mds,mgr) + 4 core cpu and 4GB RAM and 1 Gb lan
3 nodes each having 2 osd's, disks are 2TB + 2 core cpu and 4G RAM and 1
Gb lan
1 node acting as cephfs client + 2 core cpu and 4G RAM and 1 Gb lan
configured cephfs_metadata_pool (3 replica) and cephfs_data_pool erasure
2+1.
When running a script doing multiple folders creation ceph started
throwing error late IO due to high metadata workload.
once after folder creation complete PG's degraded and I am waiting for PG
to complete recovery but my OSD's starting to crash due to OOM and
restarting after some time.
Now my question is I can wait for recovery to complete but how do I stop
OOM and OSD crash? basically want to know the way to control memory usage
during recovery and make it stable.
I have also set very low PG metadata_pool 8 and data_pool 16.
I have already set "mon osd memory target to 1Gb" and I have set
max-backfill from 1 to 8.
Attached msg from "kern.log" from one of the node and snippet of error msg
in this mail.
---------error msg snippet ----------
-bash: fork: Cannot allocate memory
Sep 18 19:01:57 test-node1 kernel: [341246.765644] msgr-worker-0 invoked
oom-killer: gfp_mask=0x14200ca(GFP_HIGHUSER_MOVABLE), nodemask=(null),
order=0, oom_score_adj=0
Sep 18 19:02:00 test-node1 kernel: [341246.765645] msgr-worker-0 cpuset=/
mems_allowed=0
Sep 18 19:02:00 test-node1 kernel: [341246.765650] CPU: 1 PID: 1737 Comm:
msgr-worker-0 Not tainted 4.15.0-45-generic #48-Ubuntu
Sep 18 19:02:02 test-node1 kernel: [341246.765833] Out of memory: Kill
process 1727 (ceph-osd) score 489 or sacrifice child
Sep 18 19:02:03 test-node1 kernel: [341246.765919] Killed process 1727
(ceph-osd) total-vm:3483844kB, anon-rss:1992708kB, file-rss:0kB,
shmem-rss:0kB
Sep 18 19:02:03 test-node1 kernel: [341246.899395] oom_reaper: reaped
process 1727 (ceph-osd), now anon-rss:0kB, file-rss:0kB, shmem-rss:0kB
Sep 18 22:09:57 test-node1 kernel: [352529.433155] perf: interrupt took
too long (4965 > 4938), lowering kernel.perf_event_max_sample_rate to 40250
regards
Amudhan
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