Hi I''ve decided I want to keep an eye on the activity on my MDS, and poking about in /proc I found both /proc/fs/lustre/mds/<fsname>-MDT0000/stats and /proc/fs/lustre/mdt/MDS/mds/stats which both contain stats about metaops, but while similar they are slightly different. Now, I''m not really sure I see how they are different, and why there are two /proc/fs/lustre/md* directories with stats like that? Can somebody who knows something about lustre internals maybe shed some light on the layout of the /proc files and where to best look to get a grip on what''s going on in the file system? /andreas -- Systems Engineer PDC Center for High Performance Computing CSC School of Computer Science and Communication KTH Royal Institute of Technology SE-100 44 Stockholm, Sweden Phone: 087906658 "A satellite, an earring, and a dust bunny are what made America great!"
On 2011-03-20, at 9:09 PM, Andreas Davour wrote:> I''ve decided I want to keep an eye on the activity on my MDS, and poking about > in /proc I found both /proc/fs/lustre/mds/<fsname>-MDT0000/stats and > /proc/fs/lustre/mdt/MDS/mds/stats which both contain stats about metaops, but > while similar they are slightly different. > > Now, I''m not really sure I see how they are different, and why there are two > /proc/fs/lustre/md* directories with stats like that?I believe there is actaully a patch in bugzilla that consolidates these two /proc files, and removes one of them. I think one is just left over for compatibility reasons.> Can somebody who knows something about lustre internals maybe shed some light > on the layout of the /proc files and where to best look to get a grip on what''s > going on in the file system?There are two main different types of "stats" files - ones for the network RPC service (e.g. MDS/{mds,mds_readpage}, OSS/{ost,ost_io,ost_create}), and one for the target device (e.g. mds/<fsname>-MDT0000/, obdfilter/<fsname>-OSTnnnn). Each have slightly different statistics, because they have access to different information. I think some of this is documented in the manual. Cheers, Andreas -- Andreas Dilger Principal Engineer Whamcloud, Inc.
On Monday, March 21, 2011 08:32:59 Andreas Dilger wrote:> On 2011-03-20, at 9:09 PM, Andreas Davour wrote: > > I''ve decided I want to keep an eye on the activity on my MDS, and poking > > about in /proc I found both /proc/fs/lustre/mds/<fsname>-MDT0000/stats > > and /proc/fs/lustre/mdt/MDS/mds/stats which both contain stats about > > metaops, but while similar they are slightly different. > > > > Now, I''m not really sure I see how they are different, and why there are > > two /proc/fs/lustre/md* directories with stats like that? > > I believe there is actaully a patch in bugzilla that consolidates these two > /proc files, and removes one of them. I think one is just left over for > compatibility reasons.That would be a good thing, since they are confusing. Any hint on where to find that bugzilla entry?> > Can somebody who knows something about lustre internals maybe shed some > > light on the layout of the /proc files and where to best look to get a > > grip on what''s going on in the file system? > > There are two main different types of "stats" files - ones for the network > RPC service (e.g. MDS/{mds,mds_readpage}, OSS/{ost,ost_io,ost_create}), > and one for the target device (e.g. mds/<fsname>-MDT0000/, > obdfilter/<fsname>-OSTnnnn). > > Each have slightly different statistics, because they have access to > different information. I think some of this is documented in the manual.Thanks. I''ll take a closer look at the documentation. /andreas -- Systems Engineer PDC Center for High Performance Computing CSC School of Computer Science and Communication KTH Royal Institute of Technology SE-100 44 Stockholm, Sweden Phone: 087906658 "A satellite, an earring, and a dust bunny are what made America great!"