I upgraded a clients shared vCenter / Veeam Backup server from Windows 2003 Std x86, vCenter 4.0 U2, Veeam Backup 4.1.2 x86 to Windows 2008 Std x64, vCenter 4.1, Veeam Backup 4.1.2 x64.
The Server is a ProLiant DL380 G5 2x Quad-Core Xeon 5420 2.5GHz w/6GB RAM.
The SAN is a HP MSA 2012i Dual-Controller iSCSI SAN with 8x 15k spindles in RAID6. The two portals per controller are distributed to two iSCSI VLANs on different switches.
Both the old Windows 2003 install and the new Windows 2008 install were configured with MS iSCSI Initiator in Multipath Round-Robin mode.
NIC used for iSCSI is an HP NC364T Intel Quad-Port Gigabit Adapter with two 2GB trunks, one for each portal. Teaming was configured using the HP networking utility with IP based load balancing.
Testing using HD Tune Pro show that load balancing is working with traffic being distributed equally among the two paths and sequential throughput of about 60 MByte/s during normal workload.
After restoring the Veeam Backup DB and updating all passwords, I noticed that the vStorage SAN backups throughput was down to about 6-10 MByte/s, while switching to vStorage NBD (Network) mode, I'm seeing around 35-40 MByte/s throughput. Both monitored during full backup of same vm using task manager network monitor and backup status.
Anyone has an idea what cause this?
Under Windows 2003 vStorage SAN speed was considerably better than NBD speed.
All iSCSI ports are set to 1Gbps FD with Flow Control enabled and Jumbo Frames disabled.
All offloading functions on the intel NIC are enabled.