Subject: Re: dump incredibly slow with DAT
To: None <>
From: Bernd Sieker <>
List: netbsd-users
Date: 02/22/2001 18:02:14
On 22.02.01, 17:49:39, wrote:
> i've done first try to use dump - with my 10MB filesystem (/stand) with
> 6MB used.
> dump -0 -B 2000000 -u /stand
> does it in over 2 minutes while tar in less than 20 seconds (tar -b64 -cvf
> /dev/rst0)
> adding -b 32 or 64 to dump does not change the speed

Try dumping to stdout, and pipe the result through "buffer" (which is
in pkgsrc) to increase throughput. It does wonders when backing up
over a network connection, but might also help for local tape dumps.

i. e.:

  dump -0 -B 2000000 -u -f - /stand | buffer >/dev/nrst0

Buffer has some options to tune the size of the shared memory segment
and some other parameters, but often the defaults work just fine.

Bernd Sieker

NetBSD:  Got source?