On Sun, Jul 02, 2000 at 20:42:53 -0400, David Gilbert wrote:
"Kent" == Kent Stewart <kste...@3-cities.com> writes:
I then noticed that the IDE would crashdump somewhere around 10
times faster than the SCSI disk.
Why? Can the SCSI speed be improved?
Kent> It depends on what 2940 and what IDE drive you are talking
Kent> about. I have a Maxtor UDMA66 that is 20MB/s faster in some
I don't think this explains it at all. It would appear that the SCSI
driver is running in some "extra safe" mode, or something. It has
512M to write sequentually to a partition... and the counting on the
screen, we're looking at 2 to 3 seconds-per-megabyte (on a drive that
delivers write performance of about 10M/s in normal operation).
Maybe what I should have said that the ratio of regular operation to
dump performance of the ide driver is about 1:1 while it's 10:1 for
the SCSI driver... why is this?
When the da(4) driver does a dump, it uses the CAM transport layer's polled
completion/action facility, xpt_polled_action().
It looks like there is a substantial delay (1ms) in that routine between
If you'd like it to go faster, you'll most likely have to ask Justin about
it. (i.e., I didn't write it.)