From: keld@keldix.com
To: Stan Hoeppner <stan@hardwarefreak.com>
Cc: Phil Turmel <philip@turmel.org>, Linux RAID <linux-raid@vger.kernel.org>
Subject: Re: "Missing" RAID devices
Date: Fri, 24 May 2013 08:32:28 +0200 [thread overview]
Message-ID: <20130524063228.GB30833@www5.open-std.org> (raw)
In-Reply-To: <519EE274.5030905@hardwarefreak.com>
On Thu, May 23, 2013 at 10:45:56PM -0500, Stan Hoeppner wrote:
> On 5/23/2013 3:30 AM, keld@keldix.com wrote:
> > On Thu, May 23, 2013 at 12:59:39AM -0500, Stan Hoeppner wrote:
>
> >> You may be tempted to use md/RAID10 of some layout
> >> to optimize for writes, but you'd gain nothing, and you'd lose some
> >> performance due to overhead. The partitions you'll be using in this
> >> case are so small that they easily fit in a single physical disk track,
> >> thus no head movement is required to seek between sectors, only rotation
> >> of the platter.
> ...
> > I think a raid10,far3 is a good choice for swap, then you will enjoy
> > RAID0-like reading speed. and good write speed (compared to raid6),
> > and a chance of live surviving if just one drive keeps functioning.
>
> As I mention above, none of the md/RAID10 layouts will yield any added
> performance benefit for swap partitions. And I state the reason why.
> If you think about this for a moment you should reach the same conclusion.
I think it is you who are not fully aquainted with Linux MD. Linux
MD RAID10,far3 offers improved performance in single read, which is an
advantage for swap, when you are swapping in. Thinkk about it and try it out for yourself.
Especially if we are talking 3 drives (far3), but also when you are
talking more drives and only 2 copies. You don't get raid0 read performance in Linux
on a combination of raid1 and raid0.
best regards
keld
next prev parent reply other threads:[~2013-05-24 6:32 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-05-21 12:51 "Missing" RAID devices Jim Santos
2013-05-21 15:31 ` Phil Turmel
2013-05-21 22:22 ` Jim Santos
2013-05-22 0:02 ` Phil Turmel
2013-05-22 0:16 ` Jim Santos
2013-05-22 22:43 ` Stan Hoeppner
2013-05-22 23:26 ` Phil Turmel
2013-05-23 5:59 ` Stan Hoeppner
2013-05-23 8:30 ` keld
2013-05-24 3:45 ` Stan Hoeppner
2013-05-24 6:32 ` keld [this message]
2013-05-24 7:37 ` Stan Hoeppner
2013-05-24 17:15 ` keld
2013-05-24 19:05 ` Stan Hoeppner
2013-05-24 19:22 ` keld
2013-05-25 1:42 ` Stan Hoeppner
2013-05-24 9:23 ` David Brown
2013-05-24 18:03 ` keld
2013-05-23 8:22 ` David Brown
2013-05-21 16:23 ` Doug Ledford
2013-05-21 17:03 ` Drew
[not found] ` <519BDC8C.1040202@hardwarefreak.com>
2013-05-21 21:02 ` Drew
2013-05-21 22:06 ` Stan Hoeppner
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=20130524063228.GB30833@www5.open-std.org \
--to=keld@keldix.com \
--cc=linux-raid@vger.kernel.org \
--cc=philip@turmel.org \
--cc=stan@hardwarefreak.com \
/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).