Is there a limit or threshold point for using a network storage device with BESR 2010?

[Jon_Sumida]

I have around 75 machines on my network all using BESR 2010 and they backup to a network storage server. I have created one backup policy for all of them so it fires off all at the same time (1AM).  This is a low network activity time for my network so I didn't think there would be issues in terms of bandwidth. But recently I have users telling me they come on in the morning and they see an error message that reads:

Windows - Delayed Write Failed

Windows was unable to save all the data for the file:

\\IP STORAGE SERVER\besr_backups\trainpc1_C_Drive002_i002.iv2i. The data has been lost. This error may be caused by a failure of your computer hardware or network connection. Please try to save this file elsewhere.

Note that this is only on a handful of users, so the majority of them worked fine. We also didn't have any network connection issues reported or logged so that's not it either. The network storage server is up and running fine so it's not a hardware issue. So that got me thinking that after a certain threshold in the bandwidth that BESR disconnects or something.  Also note that the same PCs logging this error successfully backed up the next day and that the errors weren't occuring on the same day either. Just seemingly randomly. Any ideas? Is there a recommended number of clients to use per backup policy? I would think 75 is rather small compared to some other sites.

[KarbonKopy]

I have a similar amount of clients backing up and have had random errors that like yourself usually go away the next day. My NAS seems to have no issues for the most part and runs quite well in conjunction with BESR. I have found in the past such errors are usually related to the machine or software being run at the time. I would take a machine that has had the error and try to reproduce and possibly keep a list (see if the same machine does it again?). Wish I could be of more help!

[Markus_Koestler · Accepted solution]

You cold try and decrease the network throttle.

[Markus_Koestler]

Have you had a chance to try ?

[criley]

Try using the 'Distribute strategy randomly across (minutes)' option (you can find this in the schedule page for the backup policy).

This option staggers the backup for each client and should hopefully help to avoid issues like this. More details here:

http://www.symantec.com/docs/HOWTO13633

Hope that helps.

[Jon_Sumida]

Sorry for the delayed response. I've implemented a 60 minute random option today so let's see what happens.

Markus - how do I change the network throttle level?

[Markus_Koestler]

It in the console->Options->Performance->Enable network throttling

[teiva-boy]

What about the NAS not being able to handle all the disk writes?  Perhaps it's your storage that is the bottleneck?

[Jon_Sumida]

Sorry for the delayed response, I was on vacation. Okay I'm still getting PCs randomly getting that error message.

Markus - I found the network throttle option, but it's on the clients. Is there a way I can centrally manage this setting? I don't want to have to visit 300 PCs.  Reading the Help regarding network throttling it says:

Consider using this feature only when you know what your network can handle. If you schedule your backups at staggered intervals and when network traffic is low, you may not need to use this feature. Avoid backing up multiple computers at the same time and to the same network destination

The last line interests me. I have about 75 PCs backing up to one HP storage server under one policy that is set to "Distribute strategy randomly across (minutes):60". Is this too many PCs at once?

[Jon_Sumida]

teiva-boy - maybe you are on to something. I am running Windows Storage Server 2003 R2 as NAS. I'm simply sharing a directory I've named "BACKUPS" and in BESR 2010 I point to this shared folder as the backup destination. I admit I'm not real experienced in using Windows Storage Server so that's about all I did. Is there something I can check?

[Markus_Koestler]

Hm, well this could be. You might increase the 60 minutes value.  To change the network throttle from a central location you could a) script this using a vbs script b) open a BESR console and connect to each of the clients and change the setting.

[Jon_Sumida]

Markus - what would be a recommended number to use for maximum network throttling? It's based on a KB per second rate. My network runs on 100MB switch.

[Markus_Koestler]

In the cases I needed this setting 10240 was the value I used.

[Markus_Koestler]

Any updates here ?

[Jon_Sumida]

Sorry for the delay. It looks like a combination of the random distribution and network throttling worked. Not sure which one, but I am happier with the results for sure. How do I mark partial solutions?