I tried setting noout and that did
provide a bit better result. Basically I could stop the OSD on
the inactive server and everything still worked (after a 2-3
second pause) but then when I rebooted the inactive server
everything hung again until it came back online and resynced with
the cluster. This is what I saw in ceph -s:
cluster
eb2003cf-b16d-4551-adb7-892469447f89
health HEALTH_WARN 128 pgs degraded 124 pgs stuck unclean 128 pgs undersized recovery 805252/1610504 objects degraded (50.000%) mds cluster is degraded 1/2 in osds are down noout flag(s) set monmap e1: 3 mons at {FILE1=10.1.1.201:6789/0,FILE2=10.1.1.202:6789/0,MON1=10.1.1.90:6789/0} election epoch 216, quorum 0,1,2 FILE1,FILE2,MON1 fsmap e796: 1/1/1 up {0=FILE2=up:rejoin} osdmap e360: 2 osds: 1 up, 2 in; 128 remapped pgs flags noout,sortbitwise,require_jewel_osds pgmap v7056802: 128 pgs, 3 pools, 164 GB data, 786 kobjects 349 GB used, 550 GB / 899 GB avail 805252/1610504 objects degraded (50.000%) 128 active+undersized+degraded client io 1379 B/s rd, 1 op/s rd, 0 op/s wr These are the commands I ran and the
results:
ceph osd set noout
systemctl stop ceph-mds@FILE2.service
# Everything still works on the clients... systemctl stop ceph-osd@0.service # This was on FILE2 wile FILE1 was the active fsmap # Fails over quickly, can still read content on the clients.. # Rebooted FILE2 # File access on the clients locked up until FILE2 rejoined This is on Ubuntu 16 with kernel
4.4.0-141, so I'm not sure if that qualifies for David's warning
about old kernels...
Is there a command or a logfile I can
look at that will better help to diagnose this issue? Is three
servers (with only 2 OSDs) enough to run a HA cluster on ceph, or
does it just die when it doesn't have 3 active servers for a
quorum? Would installing MDS and MON on a 4th box (but sticking
with 2 OSDs) be what's required to resolve this? I really don't
want to do that, but if I have to I guess I can look into find
another box.
On 2019-01-21 5:01 p.m.,
ceph-users-request@xxxxxxxxxxxxxx wrote:
Message: 14 Date: Mon, 21 Jan 2019 10:05:15 +0100 From: Robert Sander <r.sander@xxxxxxxxxxxxxxxxxxx> To: ceph-users@xxxxxxxxxxxxxx Subject: Re: How To Properly Failover a HA Setup Message-ID: <587dac75-96bc-8719-ee62-38e71491cd20@xxxxxxxxxxxxxxxxxxx> Content-Type: text/plain; charset="utf-8" On 21.01.19 09:22, Charles Tassell wrote: Hello Everyone, ? I've got a 3 node Jewel cluster setup, and I think I'm missing something.? When I want to take one of my nodes down for maintenance (kernel upgrades or the like) all of my clients (running the kernel module for the cephfs filesystem) hang for a couple of minutes before the redundant servers kick in. Have you set the noout flag before doing cluster maintenance? ceph osd set noout and afterwards ceph osd unset noout Regards |
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