Re: New XFS benchmarks using David Chinner's recommendations for XFS-based optimizations.

[Bill Davidsen <davidsen@xxxxxxx>]

Justin Piszcz wrote:
> Dave's original e-mail:
>
> > # mkfs.xfs -f -l lazy-count=1,version=2,size=128m -i attr=2 -d 
> > agcount=4 <dev>
> > # mount -o logbsize=256k <dev> <mtpt>
>
> > And if you don't care about filsystem corruption on power loss:
>
> > # mount -o logbsize=256k,nobarrier <dev> <mtpt>
>
> > Those mkfs values (except for log size) will be hte defaults in the next
> > release of xfsprogs.
>
> > Cheers,
>
> > Dave.
> > --
> > Dave Chinner
> > Principal Engineer
> > SGI Australian Software Group
>
> ---------
>
> I used his mkfs.xfs options verbatim but I use my own mount options:
> noatime,nodiratime,logbufs=8,logbsize=26214
>
> Here are the results, the results of 3 bonnie++ averaged together for 
> each test:
> http://home.comcast.net/~jpiszcz/xfs1/result.html
>
> Thanks Dave, this looks nice--the more optimizations the better!
>
> -----------
>
> I also find it rather pecuilar that in some of my (other) benchmarks 
> my RAID 5 is just as fast as RAID 0 for extracting large files 
> (uncompressed) files:
>
> RAID 5 (1024k CHUNK)
> 26.95user 6.72system 0:37.89elapsed 88%CPU (0avgtext+0avgdata 
> 0maxresident)k0inputs+0outputs (6major+526minor)pagefaults 0swaps
>
> Compare with RAID 0 for the same operation:
>
> (as with RAID5, it appears 256k-1024k..2048k possibly) is the sweet spot.
>
> Why does mdadm still use 64k for the default chunk size?

Write performance with small files, I would think. There is some 
information in old posts, but I don't seem to find them as quickly as I 
would like.
> And another quick question, would there be any benefit to use (if it 
> were possible) a block size of > 4096 bytes with XFS (I assume only 
> IA64/similar arch can support it), e.g. x86_64 cannot because the 
> page_size is 4096.
>
> [ 8265.407137] XFS: only pagesize (4096) or less will currently work.


--
Bill Davidsen <davidsen@xxxxxxx>
 "Woe unto the statesman who makes war without a reason that will still
 be valid when the war is over..." Otto von Bismark