Replication performance problems

We have two iSCSI SANS both running iSCSI R3 v5.0 and are trying to replicate a volume between the two.

They are currently sat side by side but running through a VPN to simulate the architecture when one is moved off site.

Running through the vpn we are only getting replication task throughput of around 4388kb/s which on a 2.5TB volume will take a while to complete.

We are not using teamed NIC's; all replication traffic is through dedicated NIC's and all user storage traffic through separate NIC's.

Any suggestions as to how we can improve the throughput --- could it be anything to do with using Block I/O rather than File I/O???

Any suggestions gratefully received!

Cheers,
Carl

For doing (synchronous) volume replication, you're going to need a REALLY fast VPN. The inexpensive one we can find won't go much faster than a T1 (which is fine, since that's the only connection we'll need), but we use (asynchronous) data replication (i.e. file-level replication), so 1.5 Megabits/sec is fine for us.

I am thinking you would need a VERY fast VPN to get 40Megabytes/sec (i.e. 320 Megabits/sec), which is the default bandwidth set aside for volume replication.

BTW, is that 4388kbits/s or 4388kbytes/s?

Also check the RAID controller to make sure you have all the cache values set for performance as I have seen this cause slow replication speeds.