Hi,
we also experience hanging clients after MDS restarts; in our case we
only use a single active MDS server, and the client are actively
blacklisted by the MDS server after restart. It usually happens if the
clients are not responsive during MDS restart (e.g. being very busy).
You can check whether this is the case in your setup by inspecting the
blacklist ('ceph osd blacklist ls'). It should print the connections
which are currently blacklisted.
You can also remove entries ('ceph osd blacklist rm ...'), but be warned
that the mechanism is there for a reason. Removing a blacklisted entry
might result in file corruption if client and MDS server disagree about
the current state. Use at own risk.
We were also trying a multi active setup after upgrading to luminous,
but we were running into the same problem with the same error message.
If was probably due to old kernel clients, so in case of kernel based
cephfs I would recommend to upgrade to the latest available kernel.
As another approach you can check the current state of the cephfs
client, either by using the daemon socket in case of ceph-fuse, or the
debug information in /sys/kernel/debug/ceph/... for the kernel client.
Regards,
Burkhard
On 01.10.2018 18:34, Jaime Ibar wrote:
Hi all,
we're running a ceph 12.2.7 Luminous cluster, two weeks ago we enabled
multi mds and after few hours
these errors started showing up
2018-09-28 09:41:20.577350 mds.1 [WRN] slow request 64.421475 seconds
old, received at 2018-09-28 09:40:16.155841:
client_request(client.31059144:8544450 getattr Xs #0$
100002e1e73 2018-09-28 09:40:16.147368 caller_uid=0, caller_gid=124{})
currently failed to authpin local pins
2018-09-28 10:56:51.051100 mon.1 [WRN] Health check failed: 5 clients
failing to respond to cache pressure (MDS_CLIENT_RECALL)
2018-09-28 10:57:08.000361 mds.1 [WRN] 3 slow requests, 1 included
below; oldest blocked for > 4614.580689 secs
2018-09-28 10:57:08.000365 mds.1 [WRN] slow request 244.796854 seconds
old, received at 2018-09-28 10:53:03.203476:
client_request(client.31059144:9080057 lookup #0x100
000b7564/58 2018-09-28 10:53:03.197922 caller_uid=0, caller_gid=0{})
currently initiated
2018-09-28 11:00:00.000105 mon.1 [WRN] overall HEALTH_WARN 1 clients
failing to respond to capability release; 5 clients failing to respond
to cache pressure; 1 MDSs report slow requests,
Due to this, we decide to go back to single mds(as it worked before),
however, the clients pointing to mds.1 started hanging, however, the
ones pointing to mds.0 worked fine.
Then, we tried to enable multi mds again and the clients pointing
mds.1 went back online, however the ones pointing to mds.0 stopped work.
Today, we tried to go back to single mds, however this error was
preventing ceph to disable second active mds(mds.1)
2018-10-01 14:33:48.358443 mds.1 [WRN] evicting unresponsive client
XXXXX: (30108925), after 68213.084174 seconds
After wait for 3 hours, we restarted mds.1 daemon (as it was stuck in
stopping state forever due to the above error), we waited for it to
become active again,
unmount the problematic clients, wait for the cluster to be healthy
and try to go back to single mds again.
Apparently this worked with some of the clients, we tried to enable
multi mds again to bring faulty clients back again, however no luck
this time
and some of them are hanging and can't access to ceph fs.
This is what we have in kern.log
Oct 1 15:29:32 05 kernel: [2342847.017426] ceph: mds1 reconnect start
Oct 1 15:29:32 05 kernel: [2342847.018677] ceph: mds1 reconnect success
Oct 1 15:29:49 05 kernel: [2342864.651398] ceph: mds1 recovery completed
Not sure what else can we try to bring hanging clients back without
rebooting as they're in production and rebooting is not an option.
Does anyone know how can we deal with this, please?
Thanks
Jaime
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