From: Nuno Silva <nuno.silva@vgertech.com>
To: Eyal Lebedinsky <eyal@eyal.emu.id.au>
Cc: list linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: RAID resync speed
Date: Sat, 10 Sep 2005 03:53:47 +0100 [thread overview]
Message-ID: <43224ABB.3030002@vgertech.com> (raw)
In-Reply-To: <432240E9.9010400@eyal.emu.id.au>
Hi,
Eyal Lebedinsky wrote:
> I noticed that my 3-disk RAID was syncing at about 40MB/s, now that I
> added a fourth disk it goes at only 20+MB/s. This is on an idle machine.
3*40=120
4*20=80
> Individually, each disk measures 60+MB/s with hdparm.
And concurrent hdparms? Or some dd's concurrently?
> kernel: 2.6.13 on ia32
> Controller: Promise SATAII150 TX4
> Disks: WD 320GB SATA
>
> Q: Is this the way the raid code works? The way the disk-io is managed? Or
> could it be due to the SATA controller?
You can isolate the performance drop with some dd's. Maybe this card is
in a pci32/33mhz and you're hitting the pci bus' limits? (120~130MB/sec).
Regards,
Nuno Silva
next prev parent reply other threads:[~2005-09-10 2:53 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-09-10 2:11 Eyal Lebedinsky
2005-09-10 2:53 ` Nuno Silva [this message]
2005-09-10 3:18 ` Eyal Lebedinsky
2005-09-10 4:54 ` Nuno Silva
2005-09-10 5:16 ` Joel Jaeggli
2005-09-11 2:16 ` Eyal Lebedinsky
2005-09-12 15:57 ` Roger Heflin
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