vSphere 4.1 & vCenter: Migration taking forever, timing out

[KOMBill]

I've been chugging along for the past 6 months with everything going well.  I've migrated machines between datastores and physical hosts without incident.  Lately I"ve been having problems.  I want to move all my VMs off of a non-redundant SAN to one tha tis more reobust, but I need to use some of the hardware of the existing SAN.  This means I have ot move the VMs to a temporary SAN.  WHile I've been using Openfiler all along without any problems, the temp SAN is using MS Windows 2008 with iSCSI.  Now that I'm tryin got migrate VMs to the new datastore, they are taking forever and sometimes timing out.  I don't know how to properly debug this.  The Windows SAN has nonthing of use in any of its event logs.  vCenter doesn't tell me anything other than it takes forever and works or dies.  For instance, I started a 3GB VM migration (datastore only, disks as is) and 45 minutes later, it's at 1%.

Can someone pleas recommend what to look for?

Thanks in advance.

[bulletprooffool]

To be honest, I have found MS SANs to lack a little in performance.

I assume you have the iSCSI running over a dedicated network and are limiting the load you drop on this?

Do you have gigabit connectivity?

[KOMBill]

Thanks for your reply.

I had only decided to use the MS iSCSI solution as a stopgap measure but I don't think I will rely on it when I move forward.  Openfiler has been good to us but it takes a little longer to configure and I wanted to play with the MS solution while getting a quickie SAN up & running.

The SAN is on a GigE network with almost no load.  The LUNs in question are on a Dell RAID connected by SAS.  Some more data has appeared in the form of a Veeam alert that complained about 'host disk writet latency' and 'host disk SCSI aborts' errors.  Googling these errors doesn't return a whole lot of helpful info.

I think I'm going to try and move the VMs that are already on the MS-based SAN and then nuke it in favour of an OF-based SAN.