Hello,
When we use use either Windows RE or a third party image based full system restore into a Guest VM, the data transfer speed is painfully slow. we're talking over an hour for 52GB when it should be around 10 minutes!
here is the setup:
Server 2008 R2 hyper-v
broadcom netextreme ll 1Gbps network adapter - this connects to an iSCSI target which holds the recovery images, the iSCSI target resides on a NAS which has several disks in RAID 0 and also has 1Gbps network adapter. the transfer speed achieved to and from the Host (local disks) and NAS is getting around 100MBps, approx 80-90% of the 1Gbps adapter. this is fairly decent performance for us. the disks in the server and NAS achieve much higher than 160MBps.
second broadcom netextreme ll 1Gbps network adapter which assigned to the virtual switch, and shared with the management adapter - again, transfer speeds using this adapter on the host to the NAS is the same as the other one. the virtual machine's OS VHD file exists on a seperate iSCSI target which is on a seperate physical NAS (performance from host to NAS is fine at around 100MBps)
i offline the iSCSI target so I can attach it to the SCSI controller of the VM guest, i start the guest and perform a recovery, the data transfer speed was around 5MBps regardless of restoring a windows image or a third party image, this is nowhere near what I am expecting.
i enabled flow control on both adapters and the performance has gone up to around 10-15MBps, sometimes spiking at about 20MBps, this is still a long way off what I am expecting.
I believe this has to do with the network adapter on the hyper-v host, there must be a setting which needs adjusting but I am unsure what. if I am looking at transfer speeds to all the locations involved, I am easily getting 80MBps -110MBps depending on what I am transferring to and from various locations, so I am expecting a recovery speed within the VM guest of going a minimum of 80MBps, preferably 100MBps really.
any ideas? many thanks
Steve
