[Box Backup] Change in network usage characteristics in 0.08?

Ben Summers boxbackup@fluffy.co.uk
Sat, 27 Nov 2004 17:10:39 +0000


There were no changes in protocol behaviour in 0.08.

If you use lazy mode, the daemon is designed to send a trickle of  
backups throughout the day. So I would expect a connection to the  
server for quite a lot of the day if the clients have extensive data  
modifications to upload.

Regarding the asymmetry over the data transfer, it does seem a little  
odd. Obviously you're confident that the measuring system is correct,  
so turn on ExtendedLogging and take a look at the logs and see exactly  
what is being sent.

If a directory is modified on the client, it will request a list of  
that directory from the server until it has uploaded the files. This  
might mean it's requested once an hour with the default settings, for  
up to six hours. Might this be it?

Or if the client is a fileserver, and one of it's clients has a clock  
which is wildly out of sync, it might be downloading the directories  
all the time. Check the client logs for warnings about huge offsets,  
but, say, a 12 hour offset won't provoke the warning but continual  
filesystem write activity by that fileserver client will result in more  
queries to the server.

But as usual, a look at the logs will give more clarity over what's  
happening.

Ben




On 27 Nov 2004, at 06:02, Per Thomsen wrote:

> I have noticed in the last couple of weeks (after I installed 0.08)  
> that traffic with my box-clients has changed its behaviour: Now I have  
> a constant traffic of about 30-50 kbps outbound to the client  
> machines. Is this expected behaviour?
>
> I have 3 clients that run over the connection in question. The traffic  
> seems to be steady at about the same rate all the time, according to  
> MRTG.
>
> I stopped bbstored, and the traffic stopped immediately. As soon as I  
> start bbstored again, the traffic returns, so I'm pretty sure it's  
> bbstored that's transmitting something.
>
> Here is a snippet (names changed to protect the innocent) of nstats  
> output from my firewall for a brief period of time (about 10 minutes):
>
> Source Address      Destination Address    SPort    DPort          #    
>    bytes
> ----------------------------------------------------------------------- 
> --------
> boxsrv.example.com   client-1.isp.com      2201     2155       2002     
>  951488
> boxsrv.example.com   client-2.isp.com      2201     3568       1256     
>  493149
> boxsrv.example.com   client-2.isp.com      2201     1214       1256     
>  493059
> boxsrv.example.com   client-1.isp.com      2201     2580        241     
>  239476
> client-1.isp.com       boxsrv.example.com  2155     2201       1840     
>  182018
> client-2.isp.com       boxsrv.example.com  3568     2201       1209     
>  122606
> client-2.isp.com       boxsrv.example.com  1214     2201       1207     
>  122487
> client-1.isp.com       boxsrv.example.com  2580     2201        184     
>   15255
>
> So, from what I can read, the bbstored server is sending between 4 and  
> 5 times the amount of bytes back over the wire that it is receiving.  
> That seems odd, given that the systems are backing up, and not  
> restoring.
>
> According to bbstored logs, it seems that there are simply backups to  
> be taken *all* the time from these clients.
>
> That doesn't seem right to me, especially since these computers are  
> business computers that aren't being used at night. They have long  
> idle periods, which should result in long periods of no connection to  
> the bbstored server.
>
> Has anyone else noticed anything like this? My server is a Linux build  
> on Fedora Core2, and the clients in question are cygwin clients.
>
> Thanks in advance for any insights,
> Per
>
> -- 
> Per Reedtz Thomsen | Reedtz Consulting, LLC | F: 209 883 4119
> V: 209 883 4102    |   pthomsen@reedtz.com  | C: 209 996 9561
> GPG ID: 1209784F   |  Yahoo! Chat: pthomsen | AIM: pthomsen
>
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