lkml.org 
[lkml]   [2004]   [Feb]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: File system performance, hardware performance, ext3, 3ware RAID1, etc.


Daniel Blueman wrote:
> Willy Tarreau <willy@w.ods.org> wrote in message
> news:<1oEGw-2ex-1@gated-at.bofh.it>...
>
>>On Thu, Feb 12, 2004 at 06:32:31PM -0500, Timothy Miller wrote:
>>
>>
>>>For writes, iozone found an upper bound of about 10megs/sec, which is
>>>abysmal. Typically, I'd expect writes to be faster (on a single drive)
>>>than reads, because once the write is sent, you can forget about it.
>>>You don't have to wait around for something to come back, and that
>>>latency for reads can hurt performance. The OS can also buffer writes
>>>and reorder them in order to improve efficiency.
>>
>>It depends on the disk too. Lots of disks (specially IDE) are far slower
>>on writes than they are on reads.
>
>
> No. Have you verified this? If you 'dd' your swap partition from /dev/zero
> on IDE, you'll see write performance closely matches read performance, for
> drives old and new.
>

And this sort of things is what I find with raw writes to the model of
drive I'm using. However, it seems that there must be some issue with
the 3ware 7000-2 which is killing performance, or the way the Linux
kernel is dealing with this sorta-SCSI device.

The WD1200JB should get like 30-40 megs/sec, but when being accessed
through the 3ware, I get 10-16 megs/sec.

What could the 3ware be doing?

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 14:00    [W:0.037 / U:0.064 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site