Mirror filesystem over different network.

[Darren Poh_1]

Hi,

Is it possible to mirror a filesystem over different network, using MirrorDisk/UX? For example, remote server B at is now in adjust building to Server A in Singapore. Server B is acting a disaster recovery server, and is constantly mirror/sync with Server A using MirrorDisk/UX. The question here is that if the server B is to be move to London using a different IP address and link fibre cables as in Singapore will it work?? I notice that there is a metro clusterring but how dos it work?

Kindly advice. Thank You.

[Florian Heigl (new acc)]

metro clustering won't help in that case - it's intended to span cities, but not farther. (i.e. using fibrechannel tunneled through WDM lines)

but there are implementations of FC over IP available with most current host adapters.
Unfortunately I have no experience on that.

[Bill Hassell]

Not possible at all. LVM mirroring occurs at the driver level and is extremely careful about keeping each extent properly synced even when the disk is busy. LVM mirroring does not care anything about filesystems--it is a physical system so that raw lvols (like swap) can be mirrored. It would be useless if the local disk failed because the mirror could not be accessed over the network as a boot disk. Performance for such an arrangement would be pitiful as anything slower than a 1000Mbit link would severely slow the disk transfers...and the list goes on.

Having a disaster recovery system located so very far away means that recovery will be very complicated. What would make more sense (assuming you have an unlimited budget for the ultra-highspeed network) would be to use a smart disk array with remote mirroring. But be aware that you may still experience performance issues when the system is really busy unless you have multi-gigabit networking.