[Lustre-discuss] exceedingly slow lstats

[John White]

Well, I was reading the strace wrong anyway:
lstat("../403/a323", {st_mode=S_IFREG|0644, st_size=0, ...}) = 0 <0.134326>
getxattr("../403/a323", "system.posix_acl_access", 0x0, 0) = -1 EOPNOTSUPP (Operation not supported) <0.000018>
lstat("../403/a330", {st_mode=S_IFREG|0644, st_size=0, ...}) = 0 <0.158898>
getxattr("../403/a330", "system.posix_acl_access", 0x0, 0) = -1 EOPNOTSUPP (Operation not supported) <0.000019>
lstat("../403/a331", {st_mode=S_IFREG|0644, st_size=0, ...}) = 0 <0.239466>
getxattr("../403/a331", "system.posix_acl_access", 0x0, 0) = -1 EOPNOTSUPP (Operation not supported) <0.000012>
lstat("../403/a332", {st_mode=S_IFREG|0644, st_size=0, ...}) = 0 <0.130146>
getxattr("../403/a332", "system.posix_acl_access", 0x0, 0) = -1 EOPNOTSUPP (Operation not supported) <0.000012>

The getxattr takes an incredibly short amount of time, it's the lstat itself that's taking 0.1+s.  
----------------
John White
HPC Systems Engineer
(510) 486-7307
One Cyclotron Rd, MS: 50C-3396
Lawrence Berkeley National Lab
Berkeley, CA 94720

On Jan 20, 2012, at 2:28 PM, Mark Hahn wrote:

>> I'm sorry, I'm not quite understanding what you're asking.  I don't have
>> ACLs specifically enabled anywhere (and would expect the default is
>> disabled).
> 
> I guess what I was suggesting is that you could try a simple experiment:
> mount a client requesting the acl mount option.  (I don't know whether the "mount -oremount,acl ..." trick will work with Lustre.)
> 
> if the problem goes away, you're done.
> 
> you also mentioned OSS load - I don't see how that could be related,
> since OSSs are not involved in metadata operations like lstat or getxattr.
> (though depending on Lustre version, they could be involved in fetching
> actual size of files, which is especially salient on striped files...)
> 
> 
> 
>> ----------------
>> John White
>> HPC Systems Engineer
>> (510) 486-7307
>> One Cyclotron Rd, MS: 50C-3396
>> Lawrence Berkeley National Lab
>> Berkeley, CA 94720
>> 
>> On Jan 20, 2012, at 12:49 PM, Mark Hahn wrote:
>> 
>>>>   0.916908 getxattr("/global/scratch/jwhite/backuptest/highcount/3/a5", "system.posix_acl_access", 0x0, 0) = -1 EOPNOTSUPP (Operation not supported)
>>> 
>>> are your clients mounting with the acl option
>>> and acl isn't missing on the mds mount?
>> 
> 
> -- 
> operator may differ from spokesperson.	            hahn at mcmaster.ca