On Thu, 3 Sep 2009, Krzysztof Halasa wrote:
Ric Wheeler <rwheeler@xxxxxxxxxx> writes:
Just to add some support to this, all of the external RAID arrays that
I know of normally run with write cache disabled on the component
drives.
Do they use "off the shelf" SATA (or PATA) disks, and if so, which ones?
Which drives various vendors ships changes with specific products.
Usually, they ship drives that have carefully vetted firmware, etc.
but they are close to the same drives you buy on the open market.
But they aren't the same, are they? If they are not, the fact they can
run well with the write-through cache doesn't mean the off-the-shelf
ones can do as well.
frequently they are exactly the same drives, with exactly the same
firmware.
you disable the write caches on the drives themselves, but you add a large
write cache (with battery backup) in the raid card/chassis
Are they SATA (or PATA) at all? SCSI etc. are usually different
animals, though there are SCSI and SATA models which differ only in
electronics.
it depends on what raid array you use, some use SATA, some use SAS/SCSI
David Lang
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