Hi,
I'm unhappy with the throughput of my iscsi datastore in my vsphere environment.
The setup (in short):
- Dell N4032 10 gbit switches (all jumbo frames etc)
- New esxi 6.0 servers + vcenter 6
- Megaraid 9266-8i raid controller with 8 x 4 TB sas disks in RAID10.
- Ubuntu 14.04 on the storage server (physical machine) as the iscsi target
I've done some testing to establish a non-vmware baseline:
A: writing to local storage (raid array): 830 MB/s
B: mounted the iscsi target on other physical linux machine: 825 MB/s
C: mounted the iscsi target in a VM with vmxnet3 NIC: 500 MB/s
D: set up the iscsi target as VMFS5 datastore and then added a virtual disk to my VM and test speed: 260 MB/S
For C I expected somewhat the same performance as B, but already lose 325 MB/s there which seems to much to be only the virtualization overhead ? The same, default, iscsi settings were used.
For D: this is just too slow, only 1/3 of the speed I'm getting compared to test B.
Where do I start debugging. Did I forget settings ?
The esxi's and storage server were only hosting the test machine, so no other workload was active.
Tested the network throughput in the VM with iperf and getting the maximum network speed: 9.90 gbit/s.
Any ideas how to work this out and get decent performance ?
Best regards,
Nick