From: Stan Hoeppner <stan@hardwarefreak.com>
To: Roman Mamedov <rm@romanrm.ru>
Cc: NeilBrown <neilb@suse.de>,
Kasper Sandberg <kontakt@sandberg-consult.dk>,
linux-raid@vger.kernel.org
Subject: Re: raid6 low performance 8x3tb drives in singledegraded mode(=7x3tb)
Date: Wed, 19 Sep 2012 11:31:33 -0500 [thread overview]
Message-ID: <5059F365.8000400@hardwarefreak.com> (raw)
In-Reply-To: <20120919134030.222e4b04@natsu>
On 9/19/2012 2:40 AM, Roman Mamedov wrote:
> "/sys/block/md*/md/stripe_cache_size" is absolutely the first thing one should
> look at when facing a problem with md RAID5/6 write performance.
No. The first thing one should do is verify that the md/RAID stripe is
properly aligned to physical sector boundaries on the drives, and that
the filesystem is properly aligned to the md/RAID stripe size. If these
are not correct then tweaking stripe_cache_size isn't going to help
much, if at all.
--
Stan
next prev parent reply other threads:[~2012-09-19 16:31 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-12 0:03 raid6 low performance 8x3tb drives in singledegraded mode(=7x3tb) Kasper Sandberg
2012-09-12 9:42 ` Peter Grandi
2012-09-12 13:38 ` Peter Grandi
2012-09-19 6:25 ` NeilBrown
2012-09-19 7:40 ` Roman Mamedov
2012-09-19 16:31 ` Stan Hoeppner [this message]
2012-09-20 0:26 ` Kasper Sandberg
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=5059F365.8000400@hardwarefreak.com \
--to=stan@hardwarefreak.com \
--cc=kontakt@sandberg-consult.dk \
--cc=linux-raid@vger.kernel.org \
--cc=neilb@suse.de \
--cc=rm@romanrm.ru \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).