[dm-devel] dm howto?

[christophe varoqui]

> for right now ill probably use mdadm for the boxes we _need_ to be 
> supported, and ill start playing with dm on my debian ones. Just as a 
> side, is there a dm patch for 2.4.x that i could try?
> 
the multipath tools rely heavily on sysfs and 2.6 hotplug. There is a
kernel patch for 2.4 on ftp://sources.redhat.com/dm/ but you won't get
far with that.

> is unloading/loading the module really the only way to rescan the bus 
> with the qlogic hbas? i hate having to take an outage to add a vdisk.
> 
no, you got the following commands at disposal :
echo "scsi add-single-device 0 1 2 3">/proc/scsi/scsi
echo "scsi remove-single-device 0 1 2 3">/proc/scsi/scsi

where
0 = host adapter #
1 = bus #
2 = target #
3 = lun #

alternalively, you can google for a wrapper script written by Kurt
Garloff (I guess) named scsi-rescan.sh

> could the RH kernel be built without REPORT_LUN? would that do it?
> 
> whats your take on using the RH, HP, or qlogic versions of the hba 
> driver? is one better than the others? how does the failover work? is 
> there a doc somewhere with the module params?
> 
That is all a question of support.
For myself, I only use 2.6 for dev, which comes with the Qlogic
maintained driver.

<snip [as]symmetric laius>
> ill remember that next time we order equipment... :)
> 
not the same price either :)