Re: slow requests are blocked

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Hi JC!

Thanks for your answer first.

1. I have added output of  ceph health detail to Zabbix in case of warning. So every time I will see with which OSD the problem is.

2. I have default level of all logs. As I see here http://docs.ceph.com/docs/master/rados/troubleshooting/log-and-debug/ default log level for OSD is 1/5. Should I try

debug osd = 1/20 of 1/10 would be enough here?

3. Any thoughts why do I have Permission denied? All of my sockets are also defaults.

[cephuser@osd3 ~]$ ceph daemon osd.15 dump_historic_ops
admin_socket: exception getting command descriptions: [Errno 13] Permission denied

Thanks in advance.

Grigory Murashov
Voximplant

08.05.2018 17:31, Jean-Charles Lopez пишет:
Hi Grigory,

are these lines the only lines in your log file for OSD 15?

Just for sanity, what are the log levels you have set, if any, in your config file away from the default? If you set all log levels to 0 like some people do you may want to simply go back to the default by commenting out the debug_ lines in your config file. If you want to see something more detailed you can indeed increase the log level to 5 or 10.

What you can also do is to use the admin socket on the machine to see what operations are actually blocked: ceph daemon osd.15 dump_ops_in_flight and ceph daemon osd.15 dump_historic_ops.

These two commands and their output will show you what exact operations are blocked and will also point you to the other OSDs this OSD is working with to serve the IO. May be the culprit is actually one of the OSDs handling the subops or it could be a network problem.

Regards
JC

On May 8, 2018, at 03:11, Grigory Murashov <murashov@xxxxxxxxxxxxxx> wrote:

Hello Jean-Charles!

I have finally catch the problem, It was at 13-02.

[cephuser@storage-ru1-osd3 ~]$ ceph health detail
HEALTH_WARN 18 slow requests are blocked > 32 sec
REQUEST_SLOW 18 slow requests are blocked > 32 sec
     3 ops are blocked > 65.536 sec
     15 ops are blocked > 32.768 sec
     osd.15 has blocked requests > 65.536 sec
[cephuser@storage-ru1-osd3 ~]$


But surprise - there is no information in ceph-osd.15.log that time


2018-05-08 12:54:26.105919 7f003f5f9700  4 rocksdb: (Original Log Time 2018/05/08-12:54:26.105843) EVENT_LOG_v1 {"time_micros": 1525773266105834, "job": 2793, "event": "trivial_move", "dest
ination_level": 3, "files": 1, "total_files_size": 68316970}
2018-05-08 12:54:26.105926 7f003f5f9700  4 rocksdb: (Original Log Time 2018/05/08-12:54:26.105854) [/home/jenkins-build/build/workspace/ceph-build/ARCH/x86_64/AVAILABLE_ARCH/x86_64/AVAILABL
E_DIST/centos7/DIST/centos7/MACHINE_SIZE/huge/release/12.2.4/rpm/el7/BUILD/ceph-12.2.4/src/rocksdb/db/db_impl_compaction_flush.cc:1537] [default] Moved #1 files to level-3 68316970 bytes OK
: base level 1 max bytes base 268435456 files[0 4 45 403 722 0 0] max score 0.98

2018-05-08 13:07:29.711425 7f004f619700  4 rocksdb: [/home/jenkins-build/build/workspace/ceph-build/ARCH/x86_64/AVAILABLE_ARCH/x86_64/AVAILABLE_DIST/centos7/DIST/centos7/MACHINE_SIZE/huge/r
elease/12.2.4/rpm/el7/BUILD/ceph-12.2.4/src/rocksdb/db/db_impl_write.cc:684] reusing log 8051 from recycle list

2018-05-08 13:07:29.711497 7f004f619700  4 rocksdb: [/home/jenkins-build/build/workspace/ceph-build/ARCH/x86_64/AVAILABLE_ARCH/x86_64/AVAILABLE_DIST/centos7/DIST/centos7/MACHINE_SIZE/huge/r
elease/12.2.4/rpm/el7/BUILD/ceph-12.2.4/src/rocksdb/db/db_impl_write.cc:725] [default] New memtable created with log file: #8089. Immutable memtables: 0.

2018-05-08 13:07:29.726107 7f003fdfa700  4 rocksdb: (Original Log Time 2018/05/08-13:07:29.711524) [/home/jenkins-build/build/workspace/ceph-build/ARCH/x86_64/AVAILABLE_ARCH/x86_64/AVAILABL
E_DIST/centos7/DIST/centos7/MACHINE_SIZE/huge/release/12.2.4/rpm/el7/BUILD/ceph-12.2.4/src/rocksdb/db/db_impl_compaction_flush.cc:1158] Calling FlushMemTableToOutputFile with column family
[default], flush slots available 1, compaction slots allowed 1, compaction slots scheduled 1
2018-05-08 13:07:29.726124 7f003fdfa700  4 rocksdb: [/home/jenkins-build/build/workspace/ceph-build/ARCH/x86_64/AVAILABLE_ARCH/x86_64/AVAILABLE_DIST/centos7/DIST/centos7/MACHINE_SIZE/huge/r
elease/12.2.4/rpm/el7/BUILD/ceph-12.2.4/src/rocksdb/db/flush_job.cc:264] [default] [JOB 2794] Flushing memtable with next log file: 8089

Should I have some deeply logging?


Grigory Murashov
Voximplant

07.05.2018 18:59, Jean-Charles Lopez пишет:
Hi,

ceph health detail

This will tell you which OSDs are experiencing the problem so you can then go and inspect the logs and use the admin socket to find out which requests are at the source.

Regards
JC

On May 7, 2018, at 03:52, Grigory Murashov <murashov@xxxxxxxxxxxxxx> wrote:

Hello!

I'm not much experiensed in ceph troubleshouting that why I ask for help.

I have multiple warnings coming from zabbix as a result of ceph -s

REQUEST_SLOW: HEALTH_WARN : 21 slow requests are blocked > 32 sec

I don't see any hardware problems that time.

I'm able to find the same strings in ceph.log and ceph-mon.log like

2018-05-07 12:37:57.375546 7f3037dae700  0 log_channel(cluster) log [WRN] : Health check failed: 12 slow requests are blocked > 32 sec (REQUEST_SLOW)

Now It's important to find out the root of the problem.

How to find out:

1. which OSDs are affected

2. which particular requests were slowed and blocked?

I assume I need more detailed logging - how to do that?

Appreciate your help.

--
Grigory Murashov

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