Slow iSCSI

Hello,

i am Testing Open-E DSS7 (latest Version) on a Supermicro Hardware:

5 * 512 GByte SSD (Software Raid-5)
32 GByte RAM
Xenon E5-2620

Local Read rate is 720 MByte/s / Write Test rises an error.


I am Testing NFS and iSCSI

Network Configuration:
2 Bond's a' 2*1 Gbit Ethernet

The other Side is a ESXi 5.5 with 2*1 Gbit Ethernet
(same Hardware with 1 local SSD and 64 GByte RAM)

Now the Problem:
I am running iSCSI with Round-Robin Policy over two nics with ip adresses in different subnets. With a copy Job from ssd to iscsi i see only 48 MByte Transfer-rate (round-Robin works fine i see 2 times 24 MByte over the two vmknic).

With NFS i got 60 MByte over one wire!!!

I tried the same configuration with a Windows 2008R2 VM with I/O Meter (2 CPUs, 4 GByte RAM and 60 GByte disk with a 40 GByte I/O Meter Test-File).
- The result is equal -> nfs is round about 50% quicker then iscsi - iops and, per second and better Response time 1,9 MS nfs and 2,7 iscsi)

I take a look on the dss7 console for Performance issues but the console shows 10% cpu load and 4% Memory usage???

Thanks for your help and Happy Chrismas :)

Guenter Doerfler

Try with the changes to the Target and Initiator again with the ESX server and see if this helps.

1- one LUN per target

2- make the following changes to the targets, and initiator your ESXi 5.5:
===
1. From the console, press CTRL+ALT+W,
2. Select Tuning options -> iSCSI daemon options -> Target options,
3. Select the target in question,
4. change the values to the maximum required data size (change the initiator to match).

maxRecvDataSegmentLen=262144
MaxBurstLength= 1048576
Maxxmitdatasegment=262144
FirstBurstLength=65536
DataDigest=None
maxoutstandingr2t=8
InitialR2T=No
ImmediateData=Yes
headerDigest=None
(deprecated)Wthreads=8

Doing this will reset the iSCSI connections at each edit. Please pause any hosts connected to the LUNS.