Re: [PATCH 0/4] (RESEND) ext3[34] barrier changes

From: Chris Mason
Date: Wed May 21 2008 - 15:42:34 EST

On Wednesday 21 May 2008, Jamie Lokier wrote:
> Theodore Tso wrote:
> > On Wed, May 21, 2008 at 11:03:24AM -0700, Andrew Morton wrote:
> > > afaik there is no need to enable this feature if the machine (actually
> > > the disks) are on a UPS, yes?
> >
> > Yes, as long as you're confident that there won't be a kernel
> > bug/regression causing a lockup while the server is under severe
> > memory pressure while doing lots of fsync's, file creations, renames,
> > etc. And as long as your 100% confident that UPS's will never fail,
> > janitors will never accidentally hit the Emergency Power Office
> Can a kernel lockup cause this kind of corruption?


> Will a system reboot wipe the disk's write cache?

Only if you reboot with the power switch (some test rigs do)

> I had imagined only power loss would prevent the disk from
> writing it's cache eventually; is that wrong?

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