[Box Backup] local backups really slow

[Ben Summers]

Box Backup was intended to run over slow network connections, so I  
didn't bother spending much time optimising the protocol. It does  
send a lot of queries and blocks until they're answered, unlike rsync  
which streams. I'd like to address this in the forthcoming version,  
but in the meantime, that's a limitation.

Anyway, this means that if you have lots of small times, latency  
really kills the transfer speed, even over loopback. If you're on a  
single processor, there are lots of context switches. However, if  
you're backing up multi-Gb files, I would expect it to be relatively  
close to rsync.

Ben



On 27 Sep 2006, at 04:04, <rs@boxbackup.spam.futz.org>  
<rs@boxbackup.spam.futz.org> wrote:

> Hi,
>
> I'm trying to backup to a server running on the local machine to  
> set up a disk
> I'm going to use at a remote site. I figured a local backup would  
> be much
> faster than having to back up 40G of data over the net. However,  
> it's not
> nearly as fast as I expected. It seems to only be going at about  
> 200K/s, which
> is paltry in comparison to the M/s rates I see when doing local  
> rsyncs. The
> src and destination drives are on different IDE busses.
>
> Does that seem really slow to those of you using box backup, maybe  
> over a
> local lan? Might have have some real simple setting wrong? It's not  
> a slow
> machine - Athalon 2G, with 2.5G of memory.. CPU usage (per top) is  
> running
> about 10% user and 88% wait, and has been for several hours. The  
> client/server
> addresses are on the loopback interface.
>
> Any ideas on why it's so slow, or how I could speed it up?
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