iSCSI Question

[mattx]

Righty Ho - got our SAN talking today to my main 2003 server. Made a LUN [ 900Gig ] can connect to it etc - no problem writing data etc etc, all fine and dandy.

My question is this: - what is the best practice when assigning iSCSI targets ?

At the moment I have one port connected from our Hitachi HDS SMS100 to the switch [ there are 4 ports ] - but would I see [ or more importantly notice ] any performance loss if I created another LUN and assigned it on the same port going to the same server ?

Is there some 'best approach' pointers I should be aware of ?

[teejay]

Look at multipathing (MPIO), or link aggregation/port trunking on the switch. Both need a bit of playing with to get optimum performance and it depends on your switch/network cards etc which is going to work best.

[mattx]

Look at multipathing (MPIO), or link aggregation/port trunking on the switch. Both need a bit of playing with to get optimum performance and it depends on your switch/network cards etc which is going to work best.

 

Heh, I was looking at that earlier - but it suggest it's use in an enterprise environment - as we are only a school of 400 I brushed it aside but if you say it's worth looking at I certainly will. I will most probably setup the other ports at some stage but was wondering if there would be performance issues......

[teejay]

Yes there will, you can easily max out a 1Gb connection with iSCSI and becomes the bottleneck. Try link aggregation first as that's easier to set up, but it depends whether your server nic-switch-san talk to each other nicely using it. Easiest way to tell is set it up then copy a load of files across whilst monitoring traffic on the server, switch and SAN, you should find trafiic across all the link aggregated ports if it's working well.

[mattx]

Yes there will, you can easily max out a 1Gb connection with iSCSI and becomes the bottleneck. Try link aggregation first as that's easier to set up, but it depends whether your server nic-switch-san talk to each other nicely using it. Easiest way to tell is set it up then copy a load of files across whilst monitoring traffic on the server, switch and SAN, you should find trafiic across all the link aggregated ports if it's working well.

 

In order to do that I will have to setup the remaining ports on the SAN right ? Looks like I'll have to swot up again on the manual and assign the remaining ports !!

[teejay]

In order to do that I will have to setup the remaining ports on the SAN right ? Looks like I'll have to swot up again on the manual and assign the remaining ports !!

 

Yeah, you'll also want to have the same number of ports on your server and SAN assigned to the link, otherwise it's a bit pointless unless you've got multiple servers connected to the SAN. You'll need to install the Intel or Broadcom server software for your network cards on your server so you can link aggregate properly.