Release Notes

Host based performance

8 Best Practices for Implementing VMware vSphere in a Dell PS Series Storage Environment | TR1091 | v1.3

• Setting the Delayed ACK property globally for the iSCSI initiator

a. Under Adapter Details, select Advanced Options and click Edit.

b. Scroll down to Delayed ACK.

c. Deselect the checkbox and click OK

• Setting the Delayed ACK property for an individual discovery address

a. Under Adapter Details, select Targets, Dynamic Discovery.

b. Select the discovery address to modify and click Advanced.

d. Scroll down to Delayed ACK.

e. Deselect the checkbox for DelayedAck in the Inherited column.

f. Deselect the checkbox for DelayedAck in the Value column and click OK.

4. Do this for each discovery address that needs to be modified.

For existing connections, using the vSphere Web client:

Disabling Delayed ACK using the above procedure only disables Delayed ACK for new volumes. Any existing

volumes must use the following procedure to correct the entries already stored in the iSCSI initiator database.

1. Put ESXi node into maintenance mode.

2. To verify Delayed ACK status at the ESXi shell, enter the following command

Note: If you have Broadcom iSCSI HBAs installed, the Delayed ACK setting can be ignored if the HBAs are

not being used. In this example, the first two entries represent the Broadcom HW iSCSI HBAs.

# vmkiscsid --dump-db | grep Delayed

iSCSI MASTER Database opened. (0xff889008)

`node.conn[0].iscsi.DelayedAck`='1'

`node.conn[0].iscsi.DelayedAck`='0'

A value of “1” indicates that DelayedACK is enabled, “0” is disabled.

3. Using the vSphere Web client, click the Configure tab and in the Storage section click Storage

Adapters and select the iSCSI Software Adapter from the list.

(If you are using a HW iSCSI adapter, you must repeat this procedure for each adapter in use.)

4. Under Adapter Details, select Targets.

5. In the Static Discovery listings, select the top entry and then hold down Shift while clicking the

bottom entry.

6. Click Remove to delete all the selected entries.

7. In the Dynamic Discovery listing, remove any PS Series storage entries.

8. Reboot the node.