From: Stan Hoeppner <stan@hardwarefreak.com>
To: David Brown <david.brown@hesbynett.no>
Cc: GuoZhong Han <hanguozhong@meganovo.com>, linux-raid@vger.kernel.org
Subject: Re: make filesystem failed while the capacity of raid5 is big than 16TB
Date: Wed, 19 Sep 2012 11:00:42 -0500 [thread overview]
Message-ID: <5059EC2A.7070407@hardwarefreak.com> (raw)
In-Reply-To: <5059722D.1070409@hesbynett.no>
On 9/19/2012 2:20 AM, David Brown wrote:
> On 18/09/2012 23:38, Stan Hoeppner wrote:
>> Actually, no. The level of parallelism is the same--30 concurrent
>> writes. As noted above, the increase in performance comes from locating
>> each of the AGs on a different disk, or array. This decreases the
>> number of seeks requires per write, especially with parity arrays.
> OK, so you get 30 parallel logical writes, but if it does not translate
> into multiple parallel physical writes to the disks by having multiple
> member disks, then the gains are small.
The problem in the OP's case isn't a lack of physical write parallelism,
but most likely a problem of seek starvation caused by write parallelism.
--
Stan
next prev parent reply other threads:[~2012-09-19 16:00 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-12 7:04 make filesystem failed while the capacity of raid5 is big than 16TB vincent
2012-09-12 7:32 ` Jack Wang
2012-09-12 7:37 ` Chris Dunlop
2012-09-12 7:58 ` David Brown
[not found] ` <CACY-59cLmV2SRY+FrvhHxseDD1+r-B-3bOKPGzJdGttW+9U2mw@mail.gmail.com>
2012-09-12 9:46 ` David Brown
2012-09-12 14:13 ` Stan Hoeppner
2012-09-13 7:06 ` David Brown
2012-09-13 3:21 ` GuoZhong Han
2012-09-13 3:34 ` Mathias Buren
2012-09-13 7:13 ` David Brown
2012-09-13 7:30 ` David Brown
2012-09-13 7:43 ` John Robinson
2012-09-13 9:15 ` David Brown
2012-09-13 13:25 ` Stan Hoeppner
2012-09-13 13:52 ` David Brown
2012-09-13 22:47 ` Stan Hoeppner
2012-09-18 9:35 ` GuoZhong Han
2012-09-18 10:22 ` David Brown
2012-09-18 21:38 ` Stan Hoeppner
2012-09-19 7:20 ` David Brown
2012-09-19 16:00 ` Stan Hoeppner [this message]
2012-09-18 21:20 ` Stan Hoeppner
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