Jump to content
Sign in to follow this  
Bela

Can I restore a boot disk?

Recommended Posts

Hi,

I am using Retrospect 6 ( with latest updates) to back up 10 OSX clients+the backup computer all under OSX 10.3 with a DLT tape drive on SCSI. All seem to work fine with rare problems occasionally. I did sucessfully restore some files time to time. I thought I give it a try for a full restore, before a real disaster comes.

So I restored my TiBook system disk (replace disk content) on an external firewire disk. Just looking at the result from the finder looks OK. I chose it as startup disk ( no problem) but to my surprise it could not boot. Gray screen comes up with apple logo, but nothing happens. To find out more I tried to boot in console mode on the external disk and I got messages like:

"com.apple.kernel.bsd can not be found

con not determine immediate dependecies for extension com.apple.BootCache

...."

and similars filling the full screen and the boot process stops.

I understand that if kext-s are missing it can not boot, but I do not understand how they can be missing?

I did check that BootCache.kext IS present in /System/Libaray/Extensions/ on the restored disk.

On the other hand I do not know which extension correspond to com.apple.kernel.bsd...so this I did not check.

What can be wrong?

Aren't we supposed to be able to restore a boot disk backed up from an internal drive to an external firewire disk?

Using CarboCopyCloner ( ditto) is able to make a bootable copy of the internal disk to an extenal firewire one. So how this is supposed to work is disaster come? I bought the V6 upgrade by Internet download so I do not have an emergeny bootCD...

 

Looking forward to hear any advice how to proceed...(before real disaster hits)

 

Bela

Share this post


Link to post
Share on other sites

You say "I restored my TiBook system disk (replace disk content)" - I dont quite follow what you have dont to back / restore the TiBook hard drive. Thus, I cannot offer any advice on the problem.

 

I would guess though that you are missing essential system files.

 

I would recommend you did this a different way. I use Retrospect's Duplicate facility to backup our Xserve's hard drive. This works well and a number of times I have had to rely on it working and booted into the previous night's (or week or whatever) state of system disk.

 

Cheers

Craig.

Share this post


Link to post
Share on other sites

If you total up all the data on all 11 computers, and compare that to the total amount of data written to a Backup Set on its first Session, you'll see that by default, Retrospect does not back up every file from every machine every time.

 

Instead, it's designed to match identical files and only write them to tape once. It uses it's patneted "Snapshot" technology to keep track of the fact that these files belong on multiple machines or in multiple places on the same machine.

 

Without knowing more about your Backup procedure, it's difficult from your single experience to know what happened. But it's possible that your Snapshot did not contain all that was necessary for a happy Restore.

 

You can disable Matching, and thus insure that each and every machine has each and every file written to tape, which would, I suppose, improve Restoring a boot disk on multi-member Backup Sets (while greatly increasing the data storage needs).

 

Or you could try your test again with anouther Client Snapshot (any OS X install should be able to boot your modern PowerBook) and see what happens.

 

Or test again with a freshly created Backup Set, maybe one that has only the Retrospect machine and your TiBook client.

 

- Was the External FW drive empty when you did your Restore?

 

Dave

Share this post


Link to post
Share on other sites

Thanks for replying, apparently I was not clear enough.

 

The Mac which runs Retrospect backs up 10 clients including my laptop. It runs a new full backup every 3 months and in the mean time the backup server makes sure everybody is backed up ( incremental) every 7 days. Nothing fancy. After one of these weekly backup I went down to the backup machine and made a immediate restore choosing as source the system disk of my powerbook and using as restore place a firewire disk. I selected the option completely replace disk content. In my understanding this should restore everything on the disk as it was at the time of the last incremental backup. Now on the firewire disk I have a copy of the system disk of my laptop. (better to say not quite.) This is what I would do if my laptop's disk would eg crash. I went back to my office with the firewire disk, I attached it to my laptop and selected as statup disk. The symptoms are as I decsribed above. It is evident that an essential file is missing, the one which has the com.apple.kernel.bsd kernel extension in it. The question is WHY is it missing, or if not missing why it is not found in the boot process?

To answer Dave, the disk was empty, but anyway Retrospect replaces the content of the disk completely.

 

next round?

Bela

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

×