[Beowulf] bad bonnie++ in 14-drive RAID 10

Eugen Leitl eugen at leitl.org
Wed Sep 16 07:41:15 EDT 2009


On Wed, Sep 16, 2009 at 12:18:27PM +0100, stephen mulcahy wrote:

> I'm not sure what else people read from bonnie++ results but I normally 

I realize people mostly prefer IOZone, or similar.

> focus on the sequential output block (which I think of as "block write 
> speed" and sequential input block (which I think of as "block read 
> speed"). Smarter folk on this list may be able to provide a more 
> scientific analysis of your results than that though.
> 
> In your case, I'm reading the results below as a block write speed of 
> 455 MB/sec and a block read speed of 528 MB/sec which seems pretty good 

Thanks, this was the kind of comment I was looking for. The raw 
aggregate disk speed is roughly 770 MB/sec, so this result is not all
that bad.

This is Linux md RAID 10, CentOS 5.3

[oracle at localhost data]$ cat /proc/mdstat 
Personalities : [raid10] 
md4 : active raid10 sdp[13] sdo[12] sdn[11] sdm[10] sdl[9] sdk[8] sdj[7] sdi[6] sdh[5] sdg[4] sdf[3] sde[2] sdd[1] sdc[0]
      13674601472 blocks 64K chunks 2 near-copies [14/14] [UUUUUUUUUUUUUU]
      
unused devices: <none>

[oracle at localhost data]$ uname -a
Linux localhost.localdomain 2.6.18-128.el5xen #1 SMP Wed Jan 21 11:12:42 EST 2009 x86_64 x86_64 x86_64 GNU/Linux

Dual-socket Nehalem E5520  @ 2.27GHz, 24 GByte RAM.

> to me (unless my math has failed me). What kind of performance are you 
> expecting?

I expected slightly more, but this is adequate. Thanks again!

-- 
Eugen* Leitl <a href="http://leitl.org">leitl</a> http://leitl.org
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