Bad performance with BlockIO

[To-M]

Our Research department will review this but they will need to time to schedule testing.

[Raudi]

Hi Todd,

did you hear something?

Regards
Stefan

[To-M]

This is going to take time for them to work on this as there are many projects in front that they have to complete first. Nothing I can do now.

[Marcus]

Hi,

today I did update our iSCSI R3 Enterprise from 2.21 to 5.0 and did create new RAID and a volume with Block I/O. We use the iSCSI storage for our VMWare ESX 3.5 server virtual maschines. Inside a virtual maschine I use IOMeter to measure the disk performance and it was very weak. I was playing with the tuning options (InitialR2t = no, ImmediateData = yes) without performance boost. Now I deleted the Block I/O volume und made a new File I/O volume and get acceptable performance after playing with the tuning options.

With Block I/O I get 22 MB/s read and 5 MB/s write and with File I/O I get 57 MB/s read and 48 MB/s write (IOMeter is set to 100% sequential, 64k, 100% read or 100%write).

Any ideas?

Thanks,
Marcus

[Marcus]

One more question: I was trying this free DSS Lite last month, checked the iSCSI part and got good performance (IOMeter inside virtual maschine). Does DSS Lite use Block I/O by default and if yes, why it was so fast and iSCSI R3 Enterprise is so slow?

[masim]

DSS LITE use Block IO by default....And as far as I know both the systems are the same...

you were using same settings???

[Marcus]

Hard to say. I was using DSS Lite on another maschine, same board and NICs but older processor and less RAM. I did not configure much and I'm not sure if I created a RAID. I just had this DSS Lite to find out best settings inside the tuning options. Can RAID be the problem? With the iSCSI R3 Enterprise I use software RAID 5 on 4 harddisks, left-symmetric, 64k chunk size.

[masim]

So used a H/W RAID on one and a software for the other??

If hardware is the same and software is the same.. what is the difference here?

I was told from support to use File IO, as it seems to be using the cache better for VMware.