From: Neil Brown <neilb@suse.de>
To: Leslie Rhorer <lrhorer@satx.rr.com>
Cc: 'Johannes Truschnigg' <johannes@truschnigg.info>,
linux-raid@vger.kernel.org
Subject: Re: 3T drives and RAID
Date: Sun, 31 Oct 2010 11:30:29 -0400 [thread overview]
Message-ID: <20101031113029.226d9e65@notabene> (raw)
In-Reply-To: <B8.A4.13137.093EBCC4@cdptpa-omtalb.mail.rr.com>
On Sat, 30 Oct 2010 04:21:16 -0500
"Leslie Rhorer" <lrhorer@satx.rr.com> wrote:
> Md will automatically treat the oddball drive as if it had .5K
> sectors, or does one need to tell ma (or the kernel) to do so?
>
You don't need to tell the kernel to do anything special - it should just
work.
md/raid5 (and raid6) do all writes as 4K blocks, 4K aligned (as the
stripe-cache is made of pages which are 4K). So that fits perfectly with the
new drives.
If your filesystem issued a non-aligned read, then it could get down to the
device as a non-aligned read, but there is little performance penalty for
reads, only writes.
And XFS almost certainly does all IO in 4K multiples, so you should be fine.
In short: I can see no reason why it shouldn't work smoothly.
NeilBrown
next prev parent reply other threads:[~2010-10-31 15:30 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-10-30 3:36 3T drives and RAID Leslie Rhorer
2010-10-30 8:33 ` Johannes Truschnigg
2010-10-30 9:21 ` Leslie Rhorer
2010-10-31 15:30 ` Neil Brown [this message]
2010-10-31 19:05 ` Bernd Schubert
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