Les Mikesell wrote:

Clonezilla-live is a boot-from CD linux that will copy just the used portions of the disk and can save to another disk or image files on local disks or over the network. I'd recommend it over dd, but maybe someone has a way to do LVM snapshots so the copy can be done without a reboot.

i've generally used dump(8) and restore(8) to image ext2/3FS.... this can even be used to do an incremental dump although I rarely do that.

while i've never tried this, in theory, if you're using LVM, you can snapshot a live filesystem, then dump the unmounted snapshot to get a clean image.

note that snapshotting a database is a somewhat dicey proposition, however. I generally prefer to use the databases own dump facility rather than backing up its raw tablespace files (pg_dumpall for postgres, etc).

On Wed, Jun 25, 2008 at 1:46 PM, Les Mikesell lesmikesell@gmail.com wrote:

Hiep Nguyen wrote:

...

hi all,

i have a centos box and would like to back up just in case the hard drive fail. one way to do this is duplicate the image of the hard drive, so if the hard drive fail, just remove it and put mirrored hard drive and done.

here my system info:

uname -a Linux jadenet.jadesterling.com 2.6.9-22.0.2.EL #1 Tue Jan 17 06:51:40 CST 2006 i686 i686 i386 GNU/Linux

df -h Filesystem Size Used Avail Use% Mounted on /dev/mapper/VolGroup00-LogVol00 37G 15G 20G 43% / /dev/hda1 99M 8.9M 85M 10% /boot none 188M 0 188M 0% /dev/shm

i'm looking into dd, but is there anything better than dd?

by the way, i would like to use external hard drive via usb to do mirror image.

dd has the advantage of creating a disk that is instantly usable. The disadvantages are that you have to have it unmounted while making the copy (boot from a CD) and it takes a long time to complete since you have to copy even the unused blocks. There is also the possibility that your working disk will develop a bad spot that you don't realize until you hit it during the copy, leaving you with 2 bad disks (rotating 2 copies would avoid this issue).

Clonezilla-live is a boot-from CD linux that will copy just the used portions of the disk and can save to another disk or image files on local disks or over the network. I'd recommend it over dd, but maybe someone has a way to do LVM snapshots so the copy can be done without a reboot.

I'm downloading the .iso for clonezilla-live now. It's a very small download. 81.2 MB

Hiep Nguyen wrote:

...

...

Clonezilla-live is a boot-from CD linux that will copy just the used portions of the disk and can save to another disk or image files on local disks or over the network. I'd recommend it over dd, but maybe someone has a way to do LVM snapshots so the copy can be done without a reboot.

I'm downloading the .iso for clonezilla-live now. It's a very small download. 81.2 MB

i don't know if this is possible, but assume my centos box's motherboard goes sour, can i just take its hard drive and put on similar pc?

The disk is probably the most likely single thing to fail, but within some constraints you can move the disk around - and the same issues apply to image copies and backups. The main thing is that the driver for the disk controller has to be included in the kernel or initrd, so for example, moving a scsi disk with the boot/root partitions to a machine with a different controller will be a problem. You can fix this with some contortions to rebuild the initrd with the right modules from a rescue mode CD boot. You may also have to reconfigure the display if you have a different video card or monitor but you can normally run in text mode while doing that.