On Tue, Jan 09 2007, Neil Brown wrote:
> On Monday January 8, [EMAIL PROTECTED] wrote:
> > On Mon, 8 Jan 2007 10:08:34 +0100
> > Lars Ellenberg <[EMAIL PROTECTED]> wrote:
> > 
> > > md raidX make_request functions strip off the BIO_RW_SYNC flag,
> > > thus introducing additional latency.
> > > 
> > > fixing this in raid1 and raid10 seems to be straight forward enough.
> > > 
> > > for our particular usage case in DRBD, passing this flag improved
> > > some initialization time from ~5 minutes to ~5 seconds.
> > 
> > That sounds like a significant fix.
> > 
> > This patch also applies to 2.6.19 and I have tagged it for a -stable
> > backport.  Neil, are you OK with that?
> 
> Yes, I'm OK with that, thanks.

Ack from me as well, it's really a quite nasty bug from a performance
POV. Not just for DRDB, but for io schedulers as well.

-- 
Jens Axboe

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