[Lustre-discuss] collectl

[Andreas Dilger]

On Jul 29, 2008  14:36 -0400, Mark Seger wrote:
> One thing that confuses me about lustre counters, and maybe others, is I  
> don't really know what they mean, when they change and in fact how to  
> stimulate them to change.  For example, on my system I'm doing a watch  
> of /proc/fs/lustre/mdt/MDS/mds/stats and only see 1 reint counter,  
> because the others are all 0.  So I went and did some file renames, and  
> chmods and sure enough, the other counters did appear.  Cool!

Yes, this is expected.  We dropped the "0" counters because they are very
noisy and useless in most contexts.

> The easiest thing for me to do is to simply say that reint_setattr  
> counts the number of setattrs, but that would be a pretty weak  
> definition. When I changed did a single chmod to 100 files, setattr only  
> incremented by 1 and I expected it to increment by 100.

It should have been incremented by 100, and if it didn't it is possibly
a bug.

> want to be the one responsible for the words or all you're going to see  
> is 'reint_setattr counts the number of setattr calls' and I really don't  
> think that would be all that useful to anyone.

"reint_setattr" includes all operations that modify inode attributes,
including chmod, chown, touch, etc.

>>>>> mds_reint_create          11018837 samples [reqs] 1 1 11018837  

For mknod and mkdir operations, also used by NFS servers internally
when creating files.

>>>>> mds_reint_link            51315 samples [reqs] 1 1 51315 51315

For hard or symbolic links, like with "ln"

>>>>> mds_reint_rename         224241 samples [reqs] 1 1 224241 224241

For file and directory renames, like with "mv".

>>>>> mds_reint_unlink          13109877 samples [reqs] 1 1 13109877  

For removing files and directories, like with "rm" or "rmdir".

>>>>> mds_getxattr              36089 samples [usec] 9 8996 675208 252525110

For extended attributes and ACLs, like with "getfattr" or "getfacl".

>>>>> mds_setxattr              1230 samples [usec] 123 10110 263367  

For extended attributes and ACLs, like with "setfattr" or "setfacl".

Cheers, Andreas
--
Andreas Dilger
Sr. Staff Engineer, Lustre Group
Sun Microsystems of Canada, Inc.