Bad performance with BlockIO

[Raudi]

OK, so in my Enviroment there is in the current version FileIO the better choice.

Will there be changes in the future that more cache will be used in BlockIO? (When i'm right that the cachig in FileIO results the more performance in random IO.)

Best regards

Stefan

[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.