Quote Originally Posted by streamapps
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What is iSCSI .... normally you would say block based, but open-e recommend setting tuning options for vm volumes to FILE I/O mode instead of BLOCK I/O ?
VMWare iSCSI performance is poor, there are a number of sources on the web which say as much.

Open-e recommends File I/O because VMWare recommends File I/O...

Quote Originally Posted by streamapps
The performance gap between NFS and iSCSI i huge. Measured with IOMeter on the same physical storage target from a VMserver running on ESX the result for sequential READs at 1MB chunks is 80MB/s on iSCSI and 10MB/s on NFS volumes .....
Measuring the performance sequential operations has no context to reality.

VMWare will not be accessing the files sequentially. You need to test using random operations, reads and writes, for a better approximation of how VMWare will be accessing the drives.

Sean

P.S. Did you also know that, apparently, IOMeter generates false results on some Linux platforms?