Re: [dm-devel] Multipath conf

["Bryn M. Reeves" <bmr redhat com>]

On 06/10/2011 03:46 PM, Christophe BOULLANGER wrote:
> Hi,
> i wanna know what is that difference of both stout of multipath -ll
> <Anti-T> multipath -ll
> <Anti-T> mpath2 (350010b900004b868) dm-3 IBM-ESXS,GNA073C3ESTT0Z
> <Anti-T> [size=68G][features=0][hwhandler=0]
> <Anti-T> \_ round-robin 0 [prio=1][active]
> <Anti-T> \_ 1:0:1:0 sdc 8:32 [active][ready]
> <Anti-T> \_ round-robin 0 [prio=1][enabled]
> <Anti-T> \_ 1:0:3:0 sde 8:64 [active][ready]
> <Anti-T> c quoi la diff entre ca
> <Anti-T> et ca
> <Anti-T> orasm (36005076b0755627f4dee6fd70000002d) dm-6 IBM,1820N00
> <Anti-T> size=250G features='1 queue_if_no_path' hwhandler='0' wp=rw
> <Anti-T> `-+- policy='round-robin 0' prio=1 status=active
> <Anti-T> |- 0:0:3:0 sdb 8:16 active ready running
> <Anti-T> `- 0:0:2:0 sda 8:0 active ready running
> One have 2 tree and one both disk is on the same branch
> One is more secure ?
> Thank you for your help.
> Have a nice day.

The first one has two path groups each with one path and is configured for
failover (no load balancing of I/O). The second has one path group with both
paths in it and I/O will be balanced (round-robin) between them. This is covered
in the man page and other documentation - see the "failover" and "multibus" path
grouping policies.

Regards,
Bryn.