Ghost casting slows LAN to a crawl

[m2d2]

This is really getting on my wosits but each time I do a Ghost cast everything else on the network seems to drop out. Web browsing and media streaming stop working (erm I'm doing research at the same time ). The funning thing is, if I start Ghost from a boot disk and download the image from a share, there isn't the same problem.

 

Is ghost casting written to gobble up all bandwith when it starts?

[Gatt]

Came across this problem in my previous job - the only solution was to isolate the room being casted..

[m2d2]

Came across this problem in my previous job - the only solution was to isolate the room being casted..

 

Oh brilliant. I'm going to have get a 48 way switch and pull out the uplink

[Geoff]

You can set bandwidth limits when you use GhostCast. Additionally, make sure you using Broadcast or preferably Multicast rather than Unicast to send your ghost image to clients.

[m2d2]

You can set bandwidth limits when you use GhostCast. Additionally, make sure you using Broadcast or preferably Multicast rather than Unicast to send your ghost image to clients.

 

Yes I did set it on mulitcast but I guess I will have to play with the limit until I can find an optimal value. What speed works for you?

[fafster]

The multicasting is swamping the network. Unless you're ghosting a whole room, always use unicast.

[Geoff]

Yes I did set it on mulitcast but I guess I will have to play with the limit until I can find an optimal value. What speed works for you?

 

100mb/min? But then my LAN works properly (lots of nice new HP Procurves). Also if your using multicast, ensure you have setup your switches for multicast correctly.

 

The multicasting is swamping the network. Unless you're ghosting a whole room, always use unicast.

 

You have that the wrong way round.

[6Foot2]

What switches do you have? We are trying to tackle this issue at the moment and if my 3Com switches will support it I am told that if I enable GMNP Snoop [if I remember correctly, I can't put my hand on the notes at the moment] on the switch serving the Ghost server all should well. I am trying to make time to get round to try it, but as ever,.... Edited February 22, 2008 by 6Foot2

[localzuk]

The way I dealt with this issue is to split my network into VLANs and then alter the VLAN of of one of the ports on the ghosting server to be on the relevant vlan. That way any traffic only affects that segment of the network - which is very important to us as our phone system works on the same switches...

[andyrite]

Make sure you have igmp running on your switches.

[Trapper]

Or if you are going to multicast a whole room, start the session at 2am

[fafster]

You have that the wrong way round.

 

Could you explain?

[sahmeepee]

He means unicast will use more bandwidth than multicast if multicast is set up correctly.

 

There's some more info on setting up managed 3com switches for ghost in this recent thread:

 

http://edugeek.net/forums/showpost.php?p=158731&postcount=18

[DMcCoy]

I have no issues using multicast, even across multiple switches. I get around 600-1200 MB/m depending on a few factors.

 

If the core switch has multicast filtering then it will only affect those switches attached that do not support igmp filtering or have it disabled.

 

I completed the change to all managed procurves last july, so now the only ports to recieve ghost multicast data are those that join the igmp session.

 

I also have ghost on a seperate vlan (design and necessity - can't use 802.1x to authenticate ghost).