From: Bill Davidsen <davidsen@tmr.com>
To: "Majed B." <majedb@gmail.com>
Cc: "linux-raid@vger.kernel.org" <linux-raid@vger.kernel.org>
Subject: Re: Write-intent bitmap decreases or increase performance of RAID5?
Date: Sun, 04 Jul 2010 20:14:21 -0400 [thread overview]
Message-ID: <4C3123DD.9090509@tmr.com> (raw)
In-Reply-To: <AANLkTilnBWCGHUgQnmrzSzpo7TRYSedBVUZEOHKI4MmG@mail.gmail.com>
Majed B. wrote:
> How much RAM does your machine have?
>
> Write to the disk an amount that is larger than the amount of RAM and
> see if you get the same result.
>
> Also you can use hdparm to flush the caches before running dd the 2nd time.
>
See the meaning of the fdatasync option to dd and the
/proc/sys/vm/drop_cache control. You are right about hdparm, but it only
matters if you are using tiny data, drive caches are small.
--
Bill Davidsen <davidsen@tmr.com>
"We can't solve today's problems by using the same thinking we
used in creating them." - Einstein
next prev parent reply other threads:[~2010-07-05 0:14 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-06-29 20:11 Write-intent bitmap decreases or increase performance of RAID5? Shaochun Wang
2010-06-30 5:18 ` Roman Mamedov
2010-06-30 5:54 ` Mikael Abrahamsson
2010-06-30 5:59 ` Roman Mamedov
2010-06-30 6:58 ` Mikael Abrahamsson
2010-06-30 8:23 ` Roman Mamedov
2010-06-30 18:31 ` CoolCold
2010-07-05 0:11 ` Bill Davidsen
2010-07-01 6:40 ` Shaochun Wang
2010-07-01 20:30 ` Majed B.
2010-07-01 20:50 ` Roman Mamedov
2010-07-05 0:14 ` Bill Davidsen [this message]
2010-07-01 20:49 ` Roman Mamedov
2010-07-02 11:13 ` John Robinson
2010-07-05 0:17 ` Bill Davidsen
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