root disk restore

Latest response

hi,
i like to perform full root disk restore.
i found something like i must to restore / file system from backup on a new disk,because of open files on /.
Note: Try to avoid the unconditional overwrite of the root directory on a live file system. This is a mechanism that allows an unconditional overwrite of open files in the root directory (/) on a live file system. Performing such a restore can result in an inconsistent system that may also fail to boot. Use this option AT YOUR OWN RISK.
https://documentation.commvault.com/commvault/v11/article?p=59160.htm

if my host where i like to restore / ,has no user activity then how safe is to restore from backup / on / mounted on its default root disk?

Responses

Hello Marius Tanislav,

It is not recommended or rather system doesn't agree/allow to restore root file system online. Though there are no user/application activity happening at the moment still there are many open files which doesn't allow reverting to another version of the same file.

This should be an offline approach and also depends on how/what backup technology being adopted there, and how intact or rather good are the backup files/image. If you consider a virtual infrastructure where there is an option to take VM level snapshots and revert it easily, however, if the end systems are physical then the backup/restore approach is different. There are many open-source disaster recovery tools such as ReaR, Mondo Rescue, Bacula etc,. available which are best fit in restoring a non-bootable system, and also to restore to another working version of backup files. Without using such tools/method it would be hectic task to simply copy or rsync files to restore root file system to an earlier version. Though this is a possibility but not a recommended approach.

If you are interested in knowing how ReaR works then refer the below links: https://access.redhat.com/solutions/2115051 https://www.redhat.com/sysadmin/rear-backup-and-recover https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/system_administrators_guide/ch-relax-and-recover_rear

I hope this helps!

Hi Marius,

Once again a short answer from me : Don't even try to do that ... restore the system backup while the system is being shut down. :)

Regards,
Christian

Hi, It means that i boot from dvd,usb,pxe.In this case i have the tools to restore / in root disk?i mean i have tar,rsync?

Or maybe install OS from dvd on root disk and install client backup then restore. Or restore with tar ,rsync but in this case there are files open.I done this for core package installation and work.But i do not know it this is safe.

Hi Marius,

When you boot from an installation medium the system is NOT running and you can chroot into
the system, and use all tools that are included in the installation medium ... no files are "open". :)

Regards,
Christian

Marius,

I couldn't agree more with what my colleagues said above.

Regards,
RJ

hi, what is your approach?

Hi Marius,

What RJ said : "couldn't agree more" means NEVER perform such operations on a running system :)
The approach would be to boot from a Linux "Live" medium and do it when the system isn't running.

Regards,
Christian