Mirroring 2 IDE Drive Linux

tim.conway at philips.com tim.conway at philips.com
Tue Aug 6 14:38:02 EST 2002

A simple file-level copy won't modify the boot sectors, and even if you 
fix them independently, data won't necessarily be at the offsets expected 
by the boot code.  You should mirror one drive to the other with the dd 
command.  I'm assuming that they have identical geometry.  One more 
knowledgeable than me might be able to do dissimmilar drives, but i 
wouldn't chance it.
Ok, you say the primary master to the secondary slave.  I'm assuming the 
word secondary attached to the word slave indicates that it's on the slave 
drive on the secondary ide controller (as slave is meaningless in scsi). 
/dev/hda=master on primary ide controller, /dev/hdd=slave on secondary 
bus.  If "secondary" was redundant, and you mean a master and a slave on 
the primary ide controller, that's /dev/hdb
dd if=/dev/hda of=/dev/hdd
" will clone everything, from the first sector to the last.  If you're 
changing drive sizes, try partitioning as needed, and rsync the 
dd a kernel to a floppy, rdev it to /dev/hda1 or whatever your root 
partition is, shut down, switch the drives, boot from the floppy, run 
lilo, pop out the disk, and see if it comes back up.

Note:  This question is really not very rsync-related.  There is an 
ongoing thread about optionally syncing the contents of a raw device, 
rather than the device file itself, but I don't think that's what you're 
needing to do.  You might check comp.os.linux.bootutils.lilo, or whatever 
newsgroup handles such things.

Tim Conway
tim.conway at philips.com
303.682.4917 office, 303.921.0301 cell
Philips Semiconductor - Longmont TC
1880 Industrial Circle, Suite D
Longmont, CO 80501
Available via SameTime Connect within Philips, caesupport2 on AIM
"There are some who call me.... Tim?"

"Danny" <danny at ocsonline.com>
Sent by: rsync-admin at lists.samba.org
08/06/2002 03:01 PM

        To:     <rsync at lists.samba.org>
        cc:     (bcc: Tim Conway/LMT/SC/PHILIPS)
        Subject:        Mirroring 2 IDE Drive Linux

I have 2 drives in a Linux 7.1 server , 1 primary and 1 secondary. I am 
trying to clone to the secondary slave drive and be take the primary out 
and change the slave to primary and boot from it. The problem I am having 
is that it the copied drive will not boot, It is not getting the lilo boot 
and config properly. When I try to boot the copied drive , it boots to a 
Blank screen with an "L" in the upper left hand corner.
Can anyone tell me the proper commands to run with rsync to mirror from 
primary to secondary and boot with the copied drive properly with Redhat 
7.1 ?
If not what other solution would you recommend.
Sysadmin at ocsonline.cmo

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