I had two IBM Support Flashes in my inbox after returning from lunch. Both of which apply to SVC/V7000 software version 184.108.40.206 and VMware.
Flash #1 VMware VAAI Hardware Accelerated Locking is Not Supported With V6.4.0.x
Hardware Accelerated Locking is one of the VAAI APIs which we added support for in 6.2.0.x, and works with vSphere 4.1 and 5.0. The Hardware Accelerated Locking primitive can be disabled by navigating to the advanced settings of a vSphere host, the selecting the VMFS3 item and changing “VMFS3.HardwareAcceleratedLocking” to a zero.
Flash #2 iSCSI Hosts that Use SCSI-2 Reservations Are Not Supported with V6.4.0.x
There is an issue where SCSI-2 reservations are not removed from LUNs causing severe performance issues. With vSphere 5.0 and VAAI we can have ATS (Hardware locking) only LUNs, meaning all locking is done by the storage system. But since FLASH #1 deals directly with Hardware Locking, it doesn’t help with this Flash #2.
If you are running iSCSI with VMware, you probably want to hold off on upgrading to V220.127.116.11.