Mailinglist Archive: opensuse (1986 mails)

[Randall R Schulz <rschulz@xxxxxxxxx>]

On Wednesday 19 November 2008 10:12, Per Jessen wrote:
> Greg Freemyer wrote:
> > If you want to test it on a single drive, at least use dd to do
> > your benchmarking.
>
> These are my numbers for a 20G file on RAID1 over two SATA drives:
> > dd if=/tmp/file1 of=/tmp/file2 bs=512
> > dd if=/tmp/file1 of=/tmp/file2 bs=4k
>
> I didn't bother with those two.
>
> > dd if=/tmp/file1 of=/tmp/file2 bs=1M
>
> 27m28s  13Mb/sec
>
> > dd if=/tmp/file1 of=/tmp/file2 bs=1000M
>
> 17m34s  20Mb/sec

That's not really a correct computation. Every byte (or sector or 
whatever) must be read once and written once, and you have to account 
for both the read and the write traffic.

40 GB = 42949672960 bytes

27m28s = 1648 s
26,061,695 bytes / s

17m34s = 1054 s
40,749,215 bytes / s


> --
> /Per Jessen, Zürich


Randall Schulz
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