[LU-2375] MDS RPC stats should be under /proc/fs/lustre/mds

• Status: Resolved
• Project: Lustre
• Affects Version/s: Lustre 2.1.5, Lustre 2.4.1
• Type: Bug
• Priority: Minor
• Reporter: Andreas Dilger
• Assignee: Di Wang
• Resolution: Won't Do
• Labels: mq313
• Severity: 3

Description

In LU-718 the MDS RPC service handling is being modified to be independent of the MDT devices.

However, the current /proc files for the MDS RPC services are located under the target directory /proc/fs/lustre/mdt/

{fsname}

-MDT0000/

{mdt,mdt_*}

, but they do not relate to the target, but are instead node-wide RPC service thread statistics. They should properly be under /proc/fs/lustre/mds and/or /proc/fs/lustre/mdt/MDS/ (as they were in 1.8).

It wouldn't be a terrible idea to rename some of the service ports from their current names of "mdt_mdss", "mdt_mdsc", "mdt_fld", etc to match the 1.8 names ("mds", "mds_readpage", "mds_setattr") since they are properly "MDS" statistics. However, there may be compatibility issues that prevent renaming all of these files immediately. Creating symlinks is useful for transitioning to a new naming scheme in the future.

I've already submitted http://review.whamcloud.com/4618 to link the OSS statistics under /proc/fs/lustre/oss from their current location in /proc/fs/lustre/ost/OSS/.

Comments

[Mikhail Pershin]

considering unified server efforts that might be even better to move that under common /proc/fs/lustre/server as well as oss and mgs stats. Although we can use mds, oss and mgs separated proc directories if there are compatibility issues.

[Andreas Dilger]

Di, didn't you already have a patch for this? What is the patch number?

[Di Wang]

Hmm, those RPC services are already located under /proc/fs/lustre/mds/MDS

[root@testnode tests]# cat /proc/fs/lustre/mds/MDS/
mdt/ mdt_fld/ mdt_readpage/ mdt_seqm/ mdt_seqs/ mdt_setattr/ uuid

And I checked the code, in current implementation, these RPC service proc entry is registered in ptlrpc_register_service, since MDS will start these service, so these entry should be in MDS/ already. Please correct me, if I miss the point. Thanks.

[Andreas Dilger]

Hmm, maybe I was looking at 2.1 instead of master:

Lustre 2.1.3.50:

find /proc/fs/lustre/md[dst] -name stats
/proc/fs/lustre/mdt/myth-MDT0000/mdt_mds/stats
/proc/fs/lustre/mdt/myth-MDT0000/mdt_fld/stats
/proc/fs/lustre/mdt/myth-MDT0000/mdt_dtss/stats
/proc/fs/lustre/mdt/myth-MDT0000/mdt_mdss/stats
/proc/fs/lustre/mdt/myth-MDT0000/mdt_mdsc/stats
/proc/fs/lustre/mdt/myth-MDT0000/mdt_setattr/stats
/proc/fs/lustre/mdt/myth-MDT0000/mdt_readpage/stats
/proc/fs/lustre/mdt/myth-MDT0000/mdt/stats
/proc/fs/lustre/mdt/myth-MDT0000/exports/0@lo/stats
/proc/fs/lustre/mdt/myth-MDT0000/exports/192.168.20.159@tcp/stats
/proc/fs/lustre/mdt/myth-MDT0000/exports/192.168.20.147@tcp/stats
/proc/fs/lustre/mdt/myth-MDT0000/stats

Lustre 2.3.58:

find /proc/fs/lustre/md[dst] -name stats
/proc/fs/lustre/mds/MDS/mdt_fld/stats
/proc/fs/lustre/mds/MDS/mdt_seqm/stats
/proc/fs/lustre/mds/MDS/mdt_seqs/stats
/proc/fs/lustre/mds/MDS/mdt_setattr/stats
/proc/fs/lustre/mds/MDS/mdt_readpage/stats
/proc/fs/lustre/mds/MDS/mdt/stats
/proc/fs/lustre/mdt/testfs-MDT0000/exports/0@lo/stats
/proc/fs/lustre/mdt/testfs-MDT0000/stats

I guess it makes more sense to add a symlink in 2.1.5 from /proc/fs/lustre/mds/MDS/mds_* to /proc/fs/lustre/mdt/$fsname-MDT0000/mdt_* to keep more continuity of the stats location, since this is also where stats were located in 1.8.

Should the stats files in 2.4 also be named "mds_" instead of "mdt_", since they are really per-MDS statistics under .../mds/MDS? That would get them 100% back in line with the 1.8 stats files names.

[Andreas Dilger]

Compatibility with 1.8 is no longer a concern.