Imaging hard disk.

[studyete]

Hallo all, I'm out of idea. My problem is that i want to image my running server to an external hard disk (USB/SATA/IDE). I can not stop my serve it has to be on running. All my servers are configure on centos. I tried acronis but i can not install it to my running server.

I have an idea but i don't know how to work with this. I thought i would install acronis on my laptop which running windows os. I would connect this laptop with my server via usb port and somehow (i don't know this part.) i would get the hard disk of my linux server. to my other usb of laptop, i would connect another hard drive and image/clone my server on running situation. Is that possible anyway? or you may suggest the best way of cloning linux server.

 

[skittle]

does your server use lvm?
if so simply create a lvm snapshot
if not you should really try to do offline backup. its not really safe to image a running system.

If you are brave and want to attempt online it anyway:
use 'mondorescue', though you should stop all running applications first, especially any database.
or you can use 'tar' to make an archive of your entire filesystem.

 

[studyete]

Thanks for your reply. Actually those server are running web and mail server. I need to clone them, not image them and clone them on running situation. Dose mondo create clone or it just create image?

 

[Ijack]

I've always used the Unix "dump"/"restore" utilities to clone active filesystems. But, unfortunately, they don't work on all filesystems (ext4, for example). My server nowadays uses ZFS, so the use of snapshots solves the problem.

 

[studyete]

hallo ijack, dose your process create exact clone? i mean if i have a hdd which do not have any partition and complete blank. Will that create an exact same system so that i just remove the old system and replace the hdd?

 

[Ijack]

No, it creates a copy of the filesystem, but not at a block level. Partitioning and formatting a disk is not an onerous process, and I prefer to back up at file level; that way a corrupted file structure won't be replicated to the backup.

 

[stillblue]

Is your real problem to dump the DB and keep two copies in sync?

 

[studyete]

@stillblue, My real problem is I can not turn off those servers. What actually i wanted to do is to create clone of my servers without turning them down by just plug in a usb hard disk and clone that usb hard disk to another complete cpu with the help of acronis or clonzilla. I found acronis or clonzilla can not do cloning while system is running. I know the easy way would be to install a linux system, configure those server to that new system and just do dd or rsynk from my current running server to the new server and that will be ok. But i'm not looking for that, I just wanted to clone running system to new hdd and just plug in that hdd to a cpu. More like cloning human brain while alive and just plug the brain to a new body...lol...i know it is not possible yet

 

[dbhosttexas]

So you want to install a fresh system and migrate your existing over? Why not...

#1. Install the base OS / configure networking / patch the new host... Copying the install of the source host.
#2. Take a backup of the source server.
#3. Restore the config of the source host to the target host.

Quick, easy, no real pain involved... Of course I am assuming that since you are running mission critical (can't take the servers down) then you have an active and effective backup system. You are simply going to do a bare metal restore on the target server. Of course any errors from the source carry over, but that is to be expected...