Subject: dump is slow
To: None <>
From: Manuel Bouyer <>
List: tech-userlevel
Date: 03/02/1999 11:53:57
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.

Does someone have ideas about how to increase dump's performances ?
I'll try to add some king of cache/read ahead technique to bread() and see
if it helps.

Manuel Bouyer, LIP6, Universite Paris VI.