On Wed Mar 30, 2011 at 10:08:23AM +0200, Louis-David Mitterrand wrote:
> Hi,
>
> I am seeing horrific performance on a Dell T610 with a LSISAS2008 (Dell
> H200) card and 8 WD1002FAEX Caviar Black 1TB configured in mdadm raid6.
>
> Besides hardware, the other difference between servers is that the
> PE2900's MegaRAID has no JBOD mode so each disk must be configured as a
> "raid0" vdisk unit. On the T610 no configuration was necessary for the
> disks to "appear" in the OS. Would configuring them as raid0 vdisks
> change anything?
>
Several years ago I ran into a similar issue with a SCSI RAID controller
(may have been LSI MegaRAID, I can't recall now) and found that RAID0
vdisks were substantially faster than running it in JBOD mode. This
wasn't just down to the controller disabling caching/optimisations
either - in JBOD mode the performance was well below that on a non-RAID
controller.
Cheers,
Robin
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( ' } | Robin Hill <robin@xxxxxxxxxxxxxxx> |
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