[linux-lvm] Local + iSCSI disks

[linux-lvm] Local + iSCSI disks

[Ray Van Dolson]

Looking for thoughts on a VolGroup and LV made up of both local and
remote, iSCSI attached disks.  Obviously it will work, but are there
any settings or "gotchas" I should be aware of with this configuration?
Obviously a speed penalty...

I know I could also aggregate with the md driver and set things up to
do writes/reads to a specific disk depending on whether or not its
local, etc.  Anything like that in the LVM world?

Thanks,
Ray

Re: [linux-lvm] Local + iSCSI disks

[Bryn M. Reeves]

Ray Van Dolson wrote:
> Looking for thoughts on a VolGroup and LV made up of both local and
> remote, iSCSI attached disks.  Obviously it will work, but are there
> any settings or "gotchas" I should be aware of with this configuration?
> Obviously a speed penalty...

The period between the local devices becoming available and the iSCSI 
volumes appearing will be potentially confusing for the LVM tools and 
might need some special handling depending on how your distribution 
manages LVM activation.

In future as LVM moves to having udev detect devices and call LVM to 
have them activated this should get easier.

> I know I could also aggregate with the md driver and set things up to
> do writes/reads to a specific disk depending on whether or not its
> local, etc.  Anything like that in the LVM world?

There's the replicator target being worked on:

http://people.redhat.com/heinzm/sw/dm/dm-repl/

Regards,
Bryn.

Re: [linux-lvm] Local + iSCSI disks

[Ray Van Dolson]

On Thu, Jan 29, 2009 at 07:34:42AM -0800, Bryn M. Reeves wrote:
> 
> There's the replicator target being worked on:
> 
> http://people.redhat.com/heinzm/sw/dm/dm-repl/
> 

Huh, neat.  Will this be like DRBD only to N number of remote devices?

Ray