ESXi iSCSI initiator help

[blroot]

Hi there,

Im currently building/testing an "el cheapo" san for ESXi, and so far, i think the performance is quite ok

This is a test from a VM running Windows Server Enterprise 2008 R2 on an ESXi local datastore, using MS iSCSI initiator




As you can see it`s pretty good.

The problem is, when i use the ESXi initiator, i format the lun as vmfs, then create a vm/disk inside this datastore, i get this.



Read result is totally wrong according to network stats, it's about 25 MB/s



Just terrible, what could be the reason of this massive underperformance?

I have a dedicated gigabit switch for iSCSI traffic, using 9K jumbo frames on switch, nics, vmkernels, vmswitchs,
Target server is a xeon 3040, 8 GB ram, two Gb intel nics for iSCSI (teaming), running Windows Server Enterprise 2008 R2
Initiator (ESXi) is a dual xeon 5506 supermicro, using 1 nic for iSCSI

[anton (staff)]

Search this forum a bit. There are plenty of threads / posts about built-in ESX initiator tuning. Hint: delayed ACK and IOPS settings should be altered to "NO" and "1".

[blroot]

Already tried those recommended settings, still no luck.

Anyway, im testing ESXi 5, ATTO is giving me some good results



But if i check the network status



(vmnic1 is the iSCSI dedicated nic)
it doesn't make too much sense to me

i'll give iometer a try later.

[blroot]

Ok, i got iometer results, at least one.

Iometer read 256K sequential



Also i found one of the target's nic was taking down ther preformance



i'll run some more tests tomorrow.

[anton (staff)]

Moderate ones. But still far below expected. You're putting a wagon in front of your horse in any case. You need to tune TCP/IP stack before building storage cluster and improving iSCSI.