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Subject: Re: IBM blade server abysmal disk write performances
From: Adrian Chadd <adrian@freebsd.org>
To: Dieter BSD <dieterbsd@gmail.com>
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Cc: freebsd-hackers@freebsd.org, gibbs@freebsd.org, scottl@freebsd.org,
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On 18 January 2013 19:11, Dieter BSD <dieterbsd@gmail.com> wrote:
> Matthew writes:
>> There is also no information in the original email as to which direction
>> the I/O was being sent.
>
> In one of the followups, Karim reported:
>   # dd if=/dev/zero of=foo count=10 bs=1024000
>   10+0 records in
>   10+0 records out
>   10240000 bytes transferred in 19.615134 secs (522046 bytes/sec)
>
> 522 KB/s is pathetic.

When this is running, use gstat and see exactly how many IOPS/sec
there are and the average io size is.

Yes, 522kbytes/sec is really pathetic, but there's a lot of potential
reasons for that.


adrian