Subject: Re: dump is slow
To: None <>
From: Simon Burge <>
List: tech-userlevel
Date: 03/03/1999 11:21:50
Manuel Bouyer wrote:

> Hi,
> I am the only one to find that dump is slow ?
> Only 774 KB/s dumping to /dev/null a disk that can do 10Mb/s read/write
> throuh the filesystem.
> Changing SLAVES from 3 to 1 in tape.c increase dump speed from 40 to 100%
> on the disk I've tested (1056 KB/s for the disk above, ~400KB/s to more than
> 800KB/s on an older IDE disk). My guess is that accesses are more sequencial
> with only one slave. 1056 KB/s is still not enouth for my DLT7000.

As a data point, I just tried my DECstation 5000/260 (think _very_
roughly P90 CPU speed) running NetBSD 1.3.3 with a 5MB SCSI bus and a
2GB disk gets about 3.5MB/s on reads with bonnie and about 1.5MB/s with
dump of a 200MB root filesystem to /dev/null.

For tape backup at home I use a Exabyte 8500 - I haven't noticed dump
being too slow there ;)