[Linuxha-users] Re: Multiple apps on one server

[Simon Edwards]

Hello Michael,
	Each application must use zero, one or more unique volume groups -
typically I just use one per application. Having different sized
physical disks on the two nodes is not a problem. Since Linuxha.net
mirrors at a logical volume level only the logical volumes need to be
the same size - so you could even have different size volume groups
(though not really much point of course).

	The different sized physical devices will have no impact on the cluster
- beyond of course any physical performance differences. Indeed one host
could be on SCSI disk, the other on IDE - it would not matter as long as
the underlying logical volumes are the same size.

Hope this clarifies things for you!

Regards,
Simon.

On Mon, 2005-02-14 at 12:13 +1000, Michael Mansour wrote:
> Hi Simon,
> 
> I'm just wondering, if I wanted to have multiple applications managed on a 
> cluster, what's requirements are there on the disk layouts?
> 
> ie. is it best to have one LV per application, or one VG per application?
> 
> I'm asking because I'm trying to understand whether having different-sized 
> VG's on the primary and on the standby will have a negative impact on the 
> cluster. I know it's ideal to have the same sized disks for each cluster in 
> the node (therefore "mirroring" the VG and LV setups on each node), but I'm 
> wondering if I have one server with mirrored 120Gb disks (for example), and 
> another with mirrored 200Gb disks (for example), should I be assigning a VG on 
> each to be the same size on each? ie. like 100Gb VG's for both, and making 
> that 100Gb an LVapp1 (for example), then 20Gb VG's on both, and then making an 
> LVapp2.
> 
> I'm trying to understand this better.
> 
> Thanks.
> 
> Michael.
> 
>