We have an external USB 2 drive that we are using as a backup drive for our configuration. We use rsnapshot for the backups. It uses a few standard commands for managing snapshots:

1. rm -rf: deletes expired snapshots
2. mv: moves older snapshots down a slot
3. cp -al: duplicates last snapshot to new slot
4. rsync -a --delete --numeric-ids --relative: synchronizes new snapshot

As you could see by the log below, the majority of the time is spent on the rm -rf and the cp -al steps:

[25/Dec/2010:14:00:02] rsnapshot hourly: started
[25/Dec/2010:14:00:02] echo 21012 > /var/run/rsnapshot.pid
[25/Dec/2010:14:00:02] rm -rf /mnt/extdrive/snapshots/hourly.5/
[25/Dec/2010:14:15:48] mv /mnt/extdrive/snapshots/hourly.4/ /mnt/extdrive/snapshots/hourly.5/
[25/Dec/2010:14:15:48] mv /mnt/extdrive/snapshots/hourly.3/ /mnt/extdrive/snapshots/hourly.4/
[25/Dec/2010:14:15:48] mv /mnt/extdrive/snapshots/hourly.2/ /mnt/extdrive/snapshots/hourly.3/
[25/Dec/2010:14:15:48] mv /mnt/extdrive/snapshots/hourly.1/ /mnt/extdrive/snapshots/hourly.2/
[25/Dec/2010:14:15:48] cp -al /mnt/extdrive/snapshots/hourly.0 /mnt/extdrive/snapshots/hourly.1
[25/Dec/2010:14:23:32] rsync -a --delete --numeric-ids --relative /etc /mnt/extdrive/snapshots/hourly.0/sm4/
[25/Dec/2010:14:23:52] touch /mnt/extdrive/snapshots/hourly.0/
[25/Dec/2010:14:23:52] rm -f /var/run/rsnapshot.pid
[25/Dec/2010:14:23:52] rsnapshot hourly: completed successfully

My questions:

1. I'm currently using ext4 for the filesystem. Maybe this is not the best choice from those available in Red Hat. Anyone have any recommendations that would speed up the process?

2. The partition's mount options are sync,dirsync 1 2. Is there a way to optimize this since it's solely used for rsnapshot? Of course, reasoning would be greatly appreciated.