diff options
Diffstat (limited to 'src/ceph/doc/dev/kernel-client-troubleshooting.rst')
-rw-r--r-- | src/ceph/doc/dev/kernel-client-troubleshooting.rst | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/src/ceph/doc/dev/kernel-client-troubleshooting.rst b/src/ceph/doc/dev/kernel-client-troubleshooting.rst new file mode 100644 index 0000000..59e4761 --- /dev/null +++ b/src/ceph/doc/dev/kernel-client-troubleshooting.rst @@ -0,0 +1,17 @@ +==================================== + Kernel client troubleshooting (FS) +==================================== + +If there is an issue with the cephfs kernel client, the most important thing is +figuring out whether the problem is with the client or the MDS. Generally, +this is easy to work out. If the kernel client broke directly, there +will be output in dmesg. Collect it and any appropriate kernel state. If +the problem is with the MDS, there will be hung requests that the client +is waiting on. Look in ``/sys/kernel/debug/ceph/*/`` and cat the ``mdsc`` file to +get a listing of requests in progress. If one of them remains there, the +MDS has probably "forgotten" it. +We can get hints about what's going on by dumping the MDS cache: +ceph mds tell 0 dumpcache /tmp/dump.txt + +And if high logging levels are set on the MDS, that will almost certainly +hold the information we need to diagnose and solve the issue. |