We have been using Open-E DSS for about 18 months now and have been very impressed with features but never that impressed with performance. This has now become a major issue and I would appreciate some advise on how to improve this.

We have 2x SC836TQ-R800B chassis (16-bay SAS/SATA backplane) with SuperMicro X7DBE MB, single 5410 2330GHz, 4GB RAM and 10x Seagate Barracuda 750GB SATA drives in a RAID6 array.
We are using LSI 84016E RAID controllers on each box with 256MB cache and battery backup.
Networking is DELL 2724 gigabit web-managed switches using CAT6 cabling.
This disk space is presented to VMware using iSCSI and software initiator.
The ESX hosts are DELL PE2850 with Dual 3GHz Xeon CPUs and 16GB RAM and these use Intel 8254NXX gigabit ethernet adapters.
There are 3 LUNs on each Open-E box (1x500GB & 2x1000GB). Each of these has been initialised and is set to use FileIO. We replicate each of these 3 LUNs to the 2nd box and also use iSCSI fail-over. The Open-E boxes use Intel 80003ES2 gigabit NICs and balance-rr bonding
We are seeing very poor write performance to any drives shared through the Windows 2003 VMs, typical figures using CrystalDiskMark are

Sequential Read : 37.387 MB/s
Sequential Write : 1.635 MB/s
Random Read 512KB : 38.525 MB/s
Random Write 512KB : 1.279 MB/s
Random Read 4KB : 7.306 MB/s
Random Write 4KB : 0.208 MB/s

I must be doing something wrong here or hardware's not up to the job.

Any advice you may be able to offer in terms of tunig parameters, RAID configuration, network configuration and any benchmarks for what we should expect from this setup would be appreciated.



Thanks

Andrew