Topic: Approximate USB Backup times

[ked]

Hello all,

I've executed a backup to USB via the admin console which has been running for over 12 hours and I'm trying to determine if it is in progress or has gone horribly wrong.

The server has two 250 gb disks using standard software RAID, and the disk utilisation is at 99%. I kicked off the backup to a disk in an external USB cage as I am migrating the server onto 1.5 terabyte disks runnig SME Server 8 Beta 6.

I started the process 12 hours ago and the console screen still says "Preparing the system for backup"

Can anyone give an indication of how long I could expect the backup of 250 gb to USB to take - I understand a precise answer is impossible to give, but a ballpark figure would be great.

[janet]

ked

Even with a near full 250Gb disk I would have expected the backup to have completed by now.

Log in as root to another instance of the CLI and use
top -i
to see what is happening, and/or read the messages log file
Maybe the disk is not being written to.
Did you format it ext3, have you followed the steps here
http://wiki.contribs.org/USBDisks

[ked]

Thanks for your reply Mary.

I did follow those instructions and formatted the drive ext3. I also attempted the backup process prior to the one that is currently running, but killed it after an hour as I decided to take out one of the RAID disks for safety's sake.

At that time I checked the external drive and it had a smeserver.tgz file of about 15 gig.

Hmmm - some quick arithmatic suggest that based on 15 gig/1hr, I can expect the backup to run for 16 hrs. Maybe it will finish when I get home from work.

Seems slow though.

[lloydh]

ked,

I have a similar setup, 2 x 320GB disks mirrored and a 1TB USB drive and workstation backups configured through the admin browser.         My disks are about 50% full and with the USB disk formatted with FAT32 a full backup took 26 hours, I reformatted the disk with EXT3 and the backup now takes 19 hours which is about 7GB/hour which is still very slow.

My hardware is old, a P3 866 with IDE disks, only a couple of users but I do have a USB2 card fitted.     During the backup dar is using up to 95% of CPU so the only thing I can assume is that it is because of my old hardware.

[Jáder]

Maybe your problem is CPU usage to compress data... could you use lower compression rate/level ?

[ked]

All fixed now. It seems there was an issue with the way in which the USB drive was mounted - or not mounted!  The drive is not always recognised when its plugged in - I need to try 2-3 times before it is recognised. But that's an issue for another day (and I suspect the mobo is at fault).

The good news is that after ensuring the drive was definitely mounted the backup completed in about 5 hours. 

Thanks all for your input.

[lloydh]

jader,

Sorry but I didn't ignore your comments, I have done some testing and I have been away as well.

I tried different compression levels, the default is 6 and I went as far as 3 with CPU still at around 90%, the only significant difference at 3 was the full backup ran for more than 24 hours which caused other problems.

I also did some testing using the cp command and got some strange results.

Copying a 2.3GB file to the USB drive went at 5.3mbps which is very slow but from the USB drive it was at 23mbps, I can't explain that, obviously some sort of hardware problem and it was the same on both ports of the USB2 card.

I put a spare disk in my desktop (Athlon 1800, 1.5GB RAM and USB2) and installed 7.5.1 and to the USB drive was at 17.5mbps and from the USB drive was the same at 23mbps.

I did a test backup of 11GB of data and it ran at the equivalent of 18gb/hour which is very acceptable for me.

I then installed 8.0 beta 6 on the desktop and from the USB drive was at 25.5mbps and to the USB drive was at 26.7mbps, the same test backup equated to 20gb/hour.

On both the backup tests on the desktop the CPU usage by dar was around 90% which isn't a problem.

Conclusion, my hardware is old and tired and needs updating.

[Jáder]

Hi

Thank you by post your discovery... is only this way other persons with same problem learn without ask twice same old question.

Good luck with your new server ... and happy backups.

BTW: I use AFFA to do backups thru web!

Regards

Jáder