Mirror the server on live time
 

Hi everbody

I’ve the follow problem, and I am looking for e great solution:
We use some RHEL 4 Server, and we like to backup the whole server. But without to shutdown the server, because the services must be still available. The goal is to mirror the whole hard disk to an other system in the network.

So I think to use “dd” and “netcat” to copy the whole hard disk. But I don’t now if this idea is really good. Maybe the system performance is going to lack.

Thx for ideas

I think rsync is the weapon of choice for this.

--- rod.

yes okay, i's an idea. but with rsync, you can't copy whole partitions...

If a filesystem is mounted, you cannot reliably make copies of it. Ergo, 'dd' is not going to be useful to you. If you want to make image backups, you must unmount the partition, which may be contrary to your constraint of doing 'live' backups. If you do find it suitable to unmount a partion for making backups, may I suggest 'partimage' (Partition Image), which is good at compressing the backup image, and network friendly.

Rsync can be used to backup an entire partition, but only on a file-by-file and directory-by-directory basis (ie not an image backup). The upside of that is that you should have a ready-to-run copy of your data for recovery purposes.

---- rod.

If the 1st server is very busy and/or has a lot of files, rsync is going to take while and you'll likely end up with a set of new files that are not synchronised.
If it's just a HW failure you're worried about, consider some form of RAID eg mirror or even a cluster.
If you want a remote hot-standby, you'll need some way of duplicating the incoming TCP/IP requests.

Maybe this will help: http://amanda.zmanda.com/quick-backup-setup.html