How To Perform a Bare-Metal Backup On Linux LVM

perlow writes "Using the free System Rescue CD you can perform bare-metal backups and restores of many types of computer systems. In this article, ZDNet columnist Jason Perlow explains the multi-step procedure in detail on an LVM-based system."

Re:Sure - Don't.

[bernz]

You make sure that all your devices block devices (at least if you're in a "Real Enterprise") are at least mirrored. Just because LVM2 writes across all disks, doesn't mean you're in a single-point-of-failure mode (or RAID0 or JBOD). You just make sure your "disks" are not just a single Physical Disk, but rather a LUN composed of a RAID6 with multiple paths anf power-supplies.

And if you're not an Enterprise, this can be done on the "cheap" with RAID6 commodity boxes running as iSCSI targets.

If you're ever relying on a single device for ANYTHING you're doing it wrong. But LVM is perfectly safe if you do it in a responsible way. It just isn't necessarily super-cheap.

No! You have to use BOTH!

[khasim]

LVM is NOT the same as RAID5.

LVM makes it easy to move space around on the disks, but it does NOTHING to prevent data loss from failed disks.

Put LVM on top of a RAID 1 or RAID 5 subsystem. Then you can add / replace disks and grow the volumes to use the new space.

Re:Sure - Don't.

[pla]

If you're ever relying on a single device for ANYTHING you're doing it wrong. But LVM is perfectly safe if you do it in a responsible way.

I agree completely - And mostly meant that as my point (with an anecdote about myself as an otherwise-knowledgeable user making a really really stupid mistake).

LVM does work exactly as advertised - It just shouldn't have anywhere near the popularity it currently enjoys. For example, several Linux distros (Fedora comes to mind) set up an LVM by default. Ouch.

But yes, in the right environment (low risk of, or penalty for, failure) it solves a number of problems nicely... Adding space, something RAIDs have traditionally made painful, it makes a breeze; and volume snapshots quite simply rock the casba. But for most users (pretty much any non-enterprise level user, for that matter), I would consider it far more dangerous than helpful.

Re:Sure - Don't.

[tzanger]

LVM does work exactly as advertised - It just shouldn't have anywhere near the popularity it currently enjoys. For example, several Linux distros (Fedora comes to mind) set up an LVM by default. Ouch.

What the heck's wrong with that? I've been doing that manually on my cheap slackware systems for ages. I don't want hard partitions, and those who do are generally too young to remember the hell of C: D: E: F: G: H: drives in the old DOS days. Take a 250G drive, put a 5G / on it and LVM the rest for /usr, /home and most importantly, /var. I don't want all that shit together, and nobody is increasing the failure rate with a single drive.

Hell, I'm running LVM on my laptop, for christ's sake. It's just good sense.