swapping external hard drives

[Toomas Aas]

Hello!

OS version: 4.9-RELEASE-p1.
'device firewire' and 'device sbp' compiled into kernel.

I've bought two external FireWire drives (Maxtor 5000DV) as a cheap 
backup media. The idea is to use Amanda, define 5 "virtual tapes" on 
each disk, and swap the disk at the end of every week, keeping one of 
them off-site.

So I fdisked, disklabelled and newfsed the drives and added the 
following to /etc/fstab:

/dev/da0s1e    /backup    ufs   rw,noauto       0      0

Now I could mount the partition by just typing 'mount /backup', and 
copy files to it. Nice.

However, when I umount /backup and remove the drive, the da0 device 
somehow remains active (can be seen with 'camcontrol devlist'). When I 
then plug in the second drive, it becomes da1, which spoils all my 
beautiful backup plans. I would prefer that when I remove one drive and 
plug in the other, it becomes da0 again. So I need to get the 'old' da0 
entry to go away when unplugging the drive. How can I do that?

I tried 'camcontrol rescan 0:0:0' after disconnecting the drive, but it 
just hangs until I plug the drive back in. I tried 'camcontrol reset 
0', but this returned error 0x6 (IIRC).

The other way I can think of would be to create a script which first 
tries to 'mount /dev/da0s1e /backup' and then 'mount /dev/da1s1e 
/backup' if the former fails. But I hope there is an easier way.
--
Toomas Aas | toomas.aas at raad.tartu.ee | http://www.raad.tartu.ee/~toomas/
* MCSE - Minesweeper Consultant and Solitaire Expert