[ILUG] Mirroring a filesystem across a network

[Brendan Minish]

On Thu, 2011-02-10 at 16:32 +0000, Brian O'Mahony wrote:
> We are using LVM already. However, the issue I see with this is I want to offload the actual tarring to backup system. Having never implemented DRDB, would it allow the following in some sort of script:
> 
> LVM snapshots the filesystem
> DRDB service starts up. Mirrors the snapshot to the second server.
> DRDB service shuts down
> Second server mounts the snapshot, runs tar, and compresses everything.
> 
> Or have I misunderstood you?

We use DRDB on a couple of machines we cluster 

basically it builds a mirrored RAID that is mirrored over GigE 
on top of that we have LVM 
Each LV is only accessed by one machine at a time so I am not sure about
how snapshotting would be handled 

this guide might help 
http://www.drbd.org/users-guide/ch-lvm.html

we use this as part of a 2 node proxmox cluster for KVM virtualisation
and both nodes are 'primary' DRDB keeps the guest Virtual machines
filesystems in sync to ease live migrations 

> I am currently looking at about 800Gb of data, and that is from the last two-three years. So I am expecting it to grow quite quickly. What ever method I end up using, I have to be able to scale for obvious reasons.
> 
> B