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From: Carsten Otto <c-otto@gmx.de>
To: linux-kernel@vger.kernel.org
Subject: Re: Very poor IO performance (high CPU load), libata
Date: Sun, 16 Jul 2006 10:43:46 +0200	[thread overview]
Message-ID: <20060716084346.GA6370@server.c-otto.de> (raw)
In-Reply-To: <20060715174555.GA27640@server.c-otto.de>

Problem solved!

On Sat, Jul 15, 2006 at 07:45:57PM +0200, Carsten Otto wrote:
> In the problem case the IO wait never drops below 40% no matter how light
> the HDD load is. Logging in into the system via SSH then takes more than
> two minutes and other tasks are equally slow.

Okay, the wait percentage is no problem, but the speed is.
I had to use a second power supply for two of the four SATA disks,
because the main supply is not good enough and causes crashes and
reboots (see my other threads, I will answer there too).
In a test that checked each disk seperately I noticed that exactly those
disks connected to the second power supply perform very poor with write
accesses (65 MB/sec vs. 2 MB/sec). I replaced the second (bad) power
supply with a very good one and now all disks are working fine. My new
main power supply should arrive soon.

I still can't understand why disks work slower when provided with
"wrong" power... The disks are Maxtor MaXLine III 7V300F0.

> There might be a problem with my hardware (in a not yet determined
> device) causing this problem. But as long as I do not know what is wrong
> I still see the chance of a software error in the kernel.

Yeah, the kernel is okay :)

PS: Now a very annoying hunt for some error in my computer ends after
about three weeks. The system now is stable and fast and I am happy...

Bye and sorry for bugging you,
-- 
Carsten Otto
c-otto@gmx.de
www.c-otto.de

      reply	other threads:[~2006-07-16  9:38 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-07-15 17:45 Very poor IO performance (high CPU load), libata Carsten Otto
2006-07-16  8:43 ` Carsten Otto [this message]

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