BAB 11.5 Multiplexing!!!!

[TheMisio]

Hello,

I have got a slight problem. Recently I have converted all backup jobs on one backup server to multiplexing. After the conversion the performance of the backup jobs has dropped significantly, some of them even 10 times. Does anyone know of any known issues when using multiplexing? Are there any considerations or special requirements for using multiplexing?
Any advice appreciated....

I use BAB 11.5 on Windows 2003 Server. All client agents have also been upgraded to 11.5

Regards,

Michael

 

[vschumpy]

Could be that you are trying to use too many streams at once, and the overhead of trying to manage this actually means that the backup is slower.

 

[TheMisio]

Thanks for your reply.

I have tried many different combinations, but it still runs very slow. There are only three streams (nodes) in the parent job. Two out of those three jobs are running at around 50 MB per minute. Previously there was no problem with those particular client machines. I use multi homed backup server. All jobs within the parent one are communicating through different NICs and reside on different vlans.
Any ideas?

Thanks again....

Michael

 

[davidmichel]

Try installing this:
QO74087.CAZ 10.5 MB 11/07/05 NT -DEVICE SUPPORT UPDATE 2

 

[davidmichel]

Forgot, here is the link

http://supportconnectw.ca.com/public/storage/downloads/nt/115/basbr115-solpatch.asp

 

[vschumpy]

Although you probably don't want to hear it, and will probably strenuously deny it - it sounds like some sort of network configuation issue to me - especially as you say the server is multi-homed.

 

[TheMisio]

Thanks,

I haven't tried the patch yet so cannot comment on it. Apart that the documentation states that it addresses only a couple of tape drive issues. About the networking problems; I cannot deny anything as there's clearly a problem. My concern is why the jobs are running fine in "normal mode"? If we had any networking issues, it would be happening at all times.....
Anyway, thanks for your replies.
We are still having performance issues and still trying to resolve them.
Regards to all....

Michael

 

[deafasa]

Actually, networking issues might not show up in the normal mode of sequential backup sessions as the backup server is only accessing one backup target at a time. With Multiplexing you are streaming data from multiple sources to try and get the most efficient use of your tape drive. This puts more work on the nic cards and the network as it is the backup server is requesting more data in multiplexing mode.

Jeff

 

[TheMisio]

Thanks a lot Jeff,

We have got three backup servers with three tape drives each. Therefore, we have been backing up three different source nodes at the time. The backup servers are multihomed so we have been able to backup from three different subnets at the same time. It worked just fine untill I have converted it to multiplexing.
Still looking into it.....

Thanks again for your reply.

Michael

 

[miklaw2]

We are multiplexing here... and ran into the same problems... we ended up getting a server with more memory and that did the trick. multiplexing is memory intensive, so the more memory you have the better.
I dont know if you are having the same problems, but I thought Id share our experience. Hope you figure it out.