Re: NetBSD disk I/O

[mlelstv%serpens.de@localhost (Michael van Elst)]

ball%grex.org@localhost (Andy Ball) writes:

># mount /dev/wd1e /mnt/disk0
># cd /mnt/disk0
># dd if=/dev/zero of=TEST bs=32768 count=32768
>32768+0 records in
>32768+0 records out
>1073741824 bytes transferred in 230.022 secs (4667996 bytes/sec)
># rm TEST
># dkctl /dev/rwd1d setcache rw
># dd if=/dev/zero of=TEST bs=32768 count=32768
>32768+0 records in
>32768+0 records out
>1073741824 bytes transferred in 235.634 secs (4556820 bytes/sec)

Can you verify partition alignment? Modern disks require an alignment
of 4kbyte (8 sectors), otherwise all write operations are executed as
slow read-modify-write cycles. The effect is also somewhat true for
reading but usually hidden by the read cache.

-- 
-- 
                                Michael van Elst
Internet: mlelstv%serpens.de@localhost
                                "A potential Snark may lurk in every tree."