Duplicate / Mirror Linux Drive

toady · 07-04-2001, 07:48 AM

Hi, I am running Linux 6, Kernel 2.2.5-15 (I586), I have now installed a second hard drive (Exactly the same). I am wanting to make a mirror image on the second hard drive(from this first drive) on a daily basis for backup. What would be my best & easiset approach to solve this? The second drive must be able to be set to a primary master for booting if required. - Toady

jharris · 07-04-2001, 08:21 AM

If they're identical you can use dd to do this, either on a disk or partition level... something like

Code:

dd if=/dev/hda of=/dev/hdb bs=1k count=sizeOfHDD

or perhaps per partition

Code:

dd if=/dev/hda1 of=/dev/hdb1 bs=1k count=sizeOfPartition

but I'd look into setting up software RAID-1 - this will mirror them for you, and mask failure of a single drive, although I don't know what the story is with having / on software raid.

HTH

Jamie...

mcleodnine · 07-04-2001, 02:03 PM

Software RAID on 2.2.x kernels require a patch. I never really got root raid to work nicely until 2.4.x

For a daily backup to that drive, I would just use the following (stolen from the "Root RAID How-To") commands. This stuff doesn't require RAID to run, it's just a handy tool for copying lots of stuff.

First you need to partition and format the new (empty) drive. Please make sure it's the right one! Then mount it to something like /mnt

Code:

cd /
find . -xdev | cpio -pm /mnt

You could use this in a script and mount/copy/unmount every day.

jharris · 07-04-2001, 03:15 PM

Quote:

Originally posted by mcleodnine
Software RAID on 2.2.x kernels require a patch. I never really got root raid to work nicely until 2.4.x

Luckily I didn't need to try to RAID my root FS so I was OK on this one, do you know wether this was what the patches for 2.2 provided? I've had software RAID running fine on something like 2.2.14 (might have been a little higher, it was a while ago...).

cheers!

Jamie...

mcleodnine · 07-04-2001, 04:03 PM

IIRC the patches were necessary to get raidtools 0.91 to function. The mdutils were not able to use the fun stuff like the failed-disk directive. I don't remember if mdutils could mount a root raid fs <shrug>. I'm deleriously happy with the performance and management of RAID under 2.4.x so far. I've had reiserfs on RAID5 on my desktop box for the last three or four months and i'm impressed enough to migrate the servers to the same layout.