[Box Backup] BadBackupStoreFile

[Chris Wilson]

Hi Johann,

On Sat, 1 Sep 2007, Johann Glaser wrote:

>> It prints the banner in the MIDDLE of your bbackupquery session, AFTER 
>> you run the compare command? And then hangs? And the server is hung as 
>> well? That's pretty messed up! I can't even see how the code could do 
>> that.
>
> Oh, excuse me, I forgot to say that I started a second instance of 
> bbackupquery in another terminal window while the one with the "compare" 
> was still running.

OK, that's different :-) So was it the second bbackupquery that hung and 
left a hung process on the server, or the first?

> We have a Debian GNU/Linux 4.0 (Etch) and use the unofficial Debian 
> packages provided at http://debian.myreseau.org/dists/. The hardware 
> didn't show any problems. The backup server is the same machine as the 
> backup client. The backup store is an NFS mounted Iomega StorCenter 150d 
> 2TB (internally using RAID5, so it provides 1.5TB).
>
> I think there are two problems which come together:
> 1) large files (several GB) and a large total volume to backup (~45GB)

I'm not sure that the large total volume is significant here, but large 
files certainly are (with 0.10). But I'm afraid there is no solution to 
that problem except to upgrade.

> 2) slow backup storage mounted via NFS (Iomega StorCenter 150d 2TB)
> The backup usually starts at 3:00 and finishes between 10:00 and 12:00,
> so it runs 7-9 hours for approx. 45GB.

Do you know if it's IO bound or CPU bound on the client or server or 
whether it's the tape device that's slowing it down? How big are the usual 
incremental backups in volume of changed files? (you can get that from the 
statistics in syslog at the end of each backup run)

I suspect that because your MaximumDiffingTime is short, you are backing 
up complete copies of your large files each time, therefore writing nearly 
45GB each time. 45GB in 9 hours is about 1.4 MB/s which is not 
unreasonable for a tape device in my opinion (what is the spec for that 
device?)

Thanks again!

Cheers, Chris.
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