Topic: Server upgrade problems

[wires12]

I'm looking for suggestions and help in case I'm not thinking clearly.

Trying to migrate a server to new hardware. The data size (df -h /dev/mapper/main-root) is about 260G. I've done this before by making a backup to USB using the admin menu then applying the backup to a fresh install at the "restore from USB" prompt. The backup to USB seemed longer that usual and after 4 hours ended with a non-zero message. I assumed that meant no success so we move to plan B.

Since the server hardware is very similar moving one of the drives from the old machine to the new one seemed to work fine. We postponed rebuilding the RAID to a blank drive. The night progressed rolling out new workstations, joining the domain and cleaning up W7 desktops. Time came to move the server to the rack and go home. After working properly all night the server now will only boot to a grub prompt. Examination using a SME 8 install disk in linux rescue mode shows many missing files in /boot. This appears to me to possibly be hard drive failure.

On to plan C. After verifying that we apparently have several days of what appear to be good DAR2 backups we put the second drive from the old server in the new server. Boots to kernel panic.

Now getting ready to take a nap while plan D trundles along. Trying to make a USB backup in the old server using the second drive. If it completes we will install to a fresh install on the new server.

Questions

Does what I'm describing seem rational? Should I be doing something else?

Should 260G backup take 4 hours? Will the restore be as slow?

Is there any way to recover /home files from the drive with the defective /boot area?

[janet]

wires12

Backup to USB should work OK, speed depends on type of data files, USB port speed, external drive speed, CPU speed etc.
4 hrs for 260Gb seems quite quick, I would even say a longer time than that is probable, it depends on many factors, including CPU power etc.
Restore will take just as long possibly longer.

Try to do a small backup using DAR (use custom templates to customise the backup folders to say only /root), refer Howtos, in order to test your setup & procedure quickly. Backing up /root should only take a few minutes.

Did you format the external USB drive as ext3 or ext4 ?

Not sure what you mean by "ended with a non zero error", you need to provide the exact error message here.

You could search these forums for grub boot issues & IIRC the wiki Howto articles etc contain some useful information for troubleshooting & repairing boot problems.

You should troubleshoot your backup, you need to get a good backup before you can do a successful restore.

You can attach & mount a "faulty" drive in a working system (as a second drive), & then read & copy contents from the faulty drive, as long as the hardware allows you to (depending on surface defects etc). I'm sure there are some forums posts from long ago about this, & some tips in wiki articles, again read the howtos.

[wires12]

Thanks Janet.

The latest backup is now at 98% after 3.5 hours. The new server is setting at "Do you wish to restore from backup". Hopefully it will work this time.

This amount of time for 260 G seems slow compared to other file copies I have done. My math can be flaky but my converter program seems to indicate USB 2.0 is capable of over 200 G an hour. USB 3 would be nice but apparently SME can't find drives attached that way. In any case your assurances tell me that nothing is going wrong in that area.

I know I committed a cardinal sin by not grabbing a pix of the error message but it was quite brief and featured the phrase non-zero instead of the usual conclusion to a USB backup. If this backup terminates the same way I'll certainly be more through.

All the USB drives I use when working with SME are formatted ext3. I have used DAR for quite some time and it seems fairly stable. My point in mentioning is that the drive I'm working with isn't the only copy of the data.


I would like to know how to copy data from linux rescue's /mnt/sysimage to a USB drive. When I'm using linux rescue it does not seem to detect and connect USB drives. I usually watch /var/log/messages to monitor USB connections and nothing happens when I connect a known good USB device. It all looks very easy at http://wiki.contribs.org/Recovering_SME_Server_with_lvm_drives , Method with the official SME Server CDROM when it says "Now you have successfully mounted your LVM and you are able to read your data in a chroot environment, you can save them on a usb disk" but my question is how?

[janet]

wires12

I seem to recall there are limitations re what you can do in rescue mode.

I was referring to installing SME on a known good system, or use an existing known good install of SME,  then power down & attach the second faulty drive, then manually mount the second drive using mount command, then coping files off the second drive.
You could copy to the main drive or to a mounted USB drive.
To see what USB drives are connected & recognised do
fdisk -l
Then mount the USB drive to /mnt/..., refer to the USB drives Howto.