[PVE-User] Sorry, another doubt about LVM/iSCSI/Multipath...

[Emmanuel Kasper]

On 05/12/2016 09:35 AM, Marco Gaiarin wrote:
> 
> Sorry, again a doubt.
> 
> 
> The preferred method of using iSCSI is via ''LVM Groups with Network
> Backing'':
> 	http://pve.proxmox.com/wiki/Storage_Model#LVM_Groups_with_Network_Backing
> 
> 
> but if i use multipath, i'm just using LVM right? Eg, doing things as
> the link above or following:
> 
> 	https://pve.proxmox.com/wiki/ISCSI_Multipath
> 
> and then manually define a VG:
> 
> 	pvcreate /dev/dm-XX
> 	vgcreate MyName /dev/dm-XX
> 
> and then using as LVM tyme storage 'MyName', it is the same, right?
> 
> 

yes, if using LVM, you will create a Volume Group on top of the device
created by the multipath daemon

taking the example from the wiki

mpath0 (3600144f028f88a0000005037a95d0001) dm-3 NEXENTA,NEXENTASTOR
size=64G features='1 queue_if_no_path' hwhandler='0' wp=rw
`-+- policy='round-robin 0' prio=2 status=active
  |- 5:0:0:0 sdb 8:16 active ready running
  `- 6:0:0:0 sdc 8:32 active ready running


at that point you should do either one of

pvcreate /dev/dm-3
vgcreate MyName /dev/dm-3

or
pvreate /dev/mpath0
vgcreate MyName /dev/mpath0