Hammer performance

[Michael Neumann]

Michael Neumann wrote:
Hi,

Just compared writing a 1 GB large file with Hammer and got:

  dragnas# dd if=/dev/zero of=test count=2000000
  2000000+0 records in
  2000000+0 records out
  1024000000 bytes transferred in 26.880290 secs (38094827 bytes/sec)
When I do the same (on the same hard disk) with UFS, I get around twice
the write performance:
  dd if=/dev/zero of=test count=2000000
  2000000+0 records in
  2000000+0 records out
  1024000000 bytes transferred in 12.816585 secs (79896477 bytes/sec)
Abother strange thing occurs if I "dd" directly to the device:

  dd if=/dev/zero of=/dev/ad4s1d count=20000
  20000+0 records in
  20000+0 records out
  10240000 bytes transferred in 7.361097 secs (1391097 bytes/sec)
Here I only get around 1.4 MB/sec. Shouldn't that me a much higer value?

Regards,

  Michael