Messages in this thread | | | Date | Fri, 13 Feb 2004 17:56:40 -0500 | From | Timothy Miller <> | Subject | Re: File system performance, hardware performance, ext3, 3ware RAID1, etc. |
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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?
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