Virtualized Environment ADVICE :)

[lholland421]

Hi All, I have just started to virtualize our environment. Our setup consists of the following

 

Dell Ps6100x SAN

2 HOSTS with 4 NICS

HP 1GB Switch

 

I have got 7 viirtual machines running and they seem to be running fine. The ISCSI connection on each host uses hardly anything most of the time. However when i create a new VHD or Copy data onto a VM the ISCSI connection seems to max out.

 

Each host has 4 1GB NICS and the SAN has 2x 4 1gb NICS. Currently the hosts are setup with 1 NIC dedicated to Domain traffic and 1 NIC dedicated to ISCSI traffic.

 

Is there anything i can do to stop this from happening or anyway of increasing the ISCSI bandwidth? NIC Teaming or some sort of load balancing ?

 

Cheers Guys

[jamesfed]

What kind of Virtual Hard Disks are you creating? If they are fixed hard disks (whereby the Hypervisor creates the whole drive in one go and writes 0s to each block) it wouldn't be surprising that a 1Gbit connection would max out.

 

Also by 'copy data' how much data are we talking?

[lholland421]

Yea only when creating fixed vhds. And currently copying 100gb from a physical to the vhd and that's maxing the iscsi connection out .

 

Cheers

[jamesfed]

Ahh yes I would expect that to max any 1Gbit connection out very easily - given that 1Gbit = 125MB/s and so any respectable VHD (say 80GB) could take 10-15mins to create while maxing out the connection.

[lholland421]

Could I do some sort of Mic teaming to create a 2g connection ?

[jamesfed]

Good bit on NIC teaming here - http://www.edugeek.net/forums/wired-networks/146535-1x10gbe-10x1gbe.html

 

In short...it'll help but you won't be able to do a single 2Gbit transfer but you will be able to do 2x 1Gbit transfers. Either way it'll help and will be well worth doing if only from a redundancy POV.

[lholland421]

Cheers I'll take a Look ! Appreciate your help

[jamesfed]

No problemo

[lmgtfy]

You really need a minimum of 6 to 8 1GB connections to each server in my opinion.

 

4x dedicated to iSCSI traffic split over two switches for redundancy using the Dell hit kit for multiple connections

2x for HYPER-V host traffic (teamed and then again split over two switches)

2x for management ideally on a separate switch I say two as this will be used for backups depending on your setup and also live migrations if your running CSV which I guess you are it just a lot faster depending on RAM usage.

 

You could get away with having one switch but if it fails its not going to be good plus you might get bottlenecks when running backups or copying large files.

 

Cheers

[lholland421]

Thanks guys , I've setup mic teaming on the hosts. I have had some advice to plug the hosts straight into the San and not through a switch. What are your thoughts ?

[cpjitservices]

Plugging them directly into the SAN is a good idea if the Interfaces are there.

[bossman]

I have found that keeping your SAN connections on a different network address via 2 x 1GB switches (for failover) and having 4 Nics in each host 2 x 1GBnics (teamed) for LAN and 2 x 1GB Nics with SAN network addressing, this stops undue network traffic and also makes things run smoother and quicker.

 

I would also have 3 hosts as opposed to 2 as I like to think I have enough failover HA coverage using the 2 thirds case scenario.

 

Then again I am not an expert in virtualisation platforms only been using for the past 7 years.

 

All the above can and will work with 10GB nics and Switches its just we don't have the money to upgrade atm.