xfs_fsr question for improvement

[Michael Monnerie]

On Montag, 3. Mai 2010 Dave Chinner wrote:
> Many have. Find and tar have resisted attempts to optimise them over
> the years, so stuff like this:
> 
> http://oss.oracle.com/~mason/acp/
> grows on the interwebs all over the place... ;)

Uh, that makes a nice 3818 IOPS with 161MB/s:
xvdb              3818,16    0,80 161449,90    35,13    84,57    10,75    
2,30   0,26  99,88
And even saw >4kIOPS an 180MB/s. Nice.

The tool gave me an idea:
lvchange -r 1024 /dev/all_my_lvm_stores

And this boots copy performance a lot: With the default "-r 128" I had 
around 10-30MB/s, now 30-100MB/s. Of course this depends on the type of 
access and so on, but at least during moving back all the data from the 
backup lvm to the re-created original lvm it's a drastic speedup.

> > # time find /mountpoint/ -inum 107901420
> > real    0m30.113s
> > user    0m0.540s
> > sys     0m9.813s
> >
> > Caching helps the 2nd time :-)
> 
> That still seems rather slow traversing 750,000 cached directory
> entries. My laptop (1.3GHz CULV core2 CPU) does 465,000 directory
> entries in:
> 
> $ time sudo find / -mount -inum 123809285
> 
> real    0m2.196s
> user    0m0.384s
> sys     0m1.464s

So why was it so slow here?
As soon as moving back all data is finished, I can retry if search speed 
increased.

-- 
mit freundlichen Grüssen,
Michael Monnerie, Ing. BSc

it-management Internet Services
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