Messages in this thread | | | Date | Wed, 18 Jan 2006 10:48:51 -0500 | From | Phillip Susi <> | Subject | Re: io performance... |
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I was going to say, doesn't the kernel set the FUA bit on the write request to push important flushes through the disk's write-back cache? Like for filesystem journal flushes?
Alan Cox wrote: > 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. > > - > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ > > >
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