Performance Degradation with Data Assurance enabled Volumes and iSCSI
Applies to
- Controller Firmware (SANtricity OS) 11.40.x and later
 - iSCSI volumes with Data Assurance (DA) enabled
 - iSCSI initiator
 - Controllers:
    
- E28xx or EF280 using baseboard iSCSI ports
 - E28xx or EF280 using iSCSI ports on host interface card orderable as “HIC,E2800,16G FC/10GbE,4-ports “
 - E57xx using baseboard iSCSI ports only
 
 
Issue
- Starting with E-Series controller firmware 11.4x and including releases thereafter (i.e. 11.5x), the Data Assurance (DA; T10 PI) feature is now available with iSCSI on controllers models E28xx and E57xx/EF57x and enabled by default on volumes.
 - Due to a hardware limitation of the QLogic Hilda chipset, having DA enabled on an iSCSI volume can cause a performance degradation in read scenarios. This scenario does NOT affect the 25Gb chipset.
 - When using an iSCSI initiator to issue Reads to an iSCSI volume with DA enabled, you may experience Read performance degradation compared to a non-DA enabled iSCSI volume. The degradation is more noticeable if queue depth=1.
 - Operations such as datastore creation may time out or fail.
 - Opening a folder on VMs running at VMware ESXi using E-Series volume datastore could take about 1 minutes.
 
