raidtest for zfs

[Pawel Jakub Dawidek]

On Sat, Sep 22, 2007 at 11:24:46AM +0400, Michael Monashev wrote:
> ????????????, Pawel.
> 
> > What's strange about those results? Can you show us 'zpool status' and
> > explain what you expect and why?
> 
> > zpool status
>   pool: tank
>  state: ONLINE
>  scrub: none requested
> config:
> 
>         NAME        STATE     READ WRITE CKSUM
>         tank        ONLINE       0     0     0
>           raidz1    ONLINE       0     0     0
>             ad6s1   ONLINE       0     0     0
>             ad8s2   ONLINE       0     0     0
>             ad10s3  ONLINE       0     0     0
>             ad12s1  ONLINE       0     0     0
>             ad14s2  ONLINE       0     0     0
> 
> errors: No known data errors
> 
> I  compare  graid5,  graid3+gcache,  raidz. My target is find software
> RAID  with  better  read  performance and huge storage size. I planing
> place a lot of little (1-100kb) images on it.
> 
> Here is my test results: http://michael.mindmix.ru/168-958-rezul-taty-testirovanija-graid5-graid3-gcache-i-raidz.zhtml
> 
> graid3+gcache with round-robin reading is 1.25 faster than 1 disk.
> graid5 is 2.18 faster than 1 disk.
> raidz is 7.7 faster than 1 disk.
> 
> 5 disks cant read faster than 5 times. raidz is 7.7 faster than 1
> disk!
> 
> This is strange for me.

ZFS ZVOL doesn't present raw blocks to use, like graid3/graid5, so it's
quite possible that because of how the data was written and how ZFS
prefetches the data it's faster than one disk.

You may want to compare one raw disk to single disk pool.

-- 
Pawel Jakub Dawidek                       http://www.wheel.pl
pjd at FreeBSD.org                           http://www.FreeBSD.org
FreeBSD committer                         Am I Evil? Yes, I Am!
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