On Aug 26, 2004, at 3:54 PM, Doug McNaught wrote:
Kevin Barnard <[EMAIL PROTECTED]> writes:
Actually you are both are right and wrong. The XRaid uses
FibreChannel to communicate to the host machine(s). The Raid
controller is a FibreChannel controller. After that there is a
FibreChannel to UltraATA conversion for each drive, separate ATA bus
for each drive.
What I am curious about is if this setup gets around ATA fsync
problems, where the drive reports the write before it is actually
performed.
Good point.
(a) The FC<->ATA unit hopefully has a battery-backed cache, which would make the whole thing more robust against power loss.
Each controller is battery backed (pretty beefy batteries too). Actually, they are optional,
but if you spend the money for the unit and leave off the battery you should
have your head examined.
(b) Since Apple is the vendor for the drive units, they can buy ATA
drives that don't lie about cache flushes. Whether they do or not
is definitely a question. ;)
Given what they charge for them I would like to think so...but who knows...
The ones in mine are from Hitachi, model #HDS722525VLAT80.
-Doug -- Let us cross over the river, and rest under the shade of the trees. --T. J. Jackson, 1863
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