[Lustre-discuss] collectl

[Mark Seger]

Kilian CAVALOTTI wrote:
> Hi Mark,
>
>   
>> useful. I suppose one might also make that argument about things like
>> statfs, getattr - the only time I was able to make them change was in
>> response to lfs commands. Might that logic also be applied to
>> extended attributes and acl counters which I suspect also fall into
>> the category of slowly changing counters?  
>>     
>
> If you have ACLs enabled on your MDS, then every "ls -l" will induce 
> getxattr()s and the mds_getxattr counter will be increased by as much. 
> So this can change quickly. mds_setxattr, on the other hand, may change 
> less often, since you usually set ACLs less often than you list files. 
> But it can still be interesting to see if mds_setxattr goes through the 
> roof.
>   
so here's the test I did.  I created 200 files and set acls on all of 
them.  setxattr changed by 200.  then I did an ls -l on the directory 
with the files in it and getxattr changed by 1.  when I removed all the 
files reint changed by 200.  I should quickly point out this was done on 
a 1.6.4 system as I'm waiting for access to remount the mds on my 1.6.5 
systems with acls enabled.
-mark