Messages in this thread | | | Subject | Re: io performance... | From | Alan Cox <> | Date | Wed, 18 Jan 2006 09:21:04 +0000 |
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On Maw, 2006-01-17 at 21:30 -0700, Jeff V. Merkey wrote: > > How can I force it to be 'write back'? > Forcing write back is a very bad idea unless you have a battery backed > up RAID controller.
Not always. If you have a cache flush command and the OS knows about using it, or if you don't care if the data gets lost over a power failure (eg /tmp and swap) it makes sense to force it.
The raid controller drivers that fake scsi don't always fake enough of scsi to report that they support cache flushes and the like. That doesn't mean the controller itself is neccessarily doing one thing or the other.
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