Equallogic hosts with Windows
Install the HIT kit - Show/Hide
Download the setup file from www.equallogic.com
Run the downloaded file and choose all the default options. Unless the old version is below 3.5 you can just run it over the top, otherwise uninstall the older version and reinstall the new version from scratch.
Disable TCP delayed ACK - Show/Hide
How to disable Delayed ACKs in Windows
Delayed Acknowledgment is used to reduce the number of packets sent on the media. Instead of sending an acknowledgmentfor each TCP segment received, TCP will send an acknowledgment back only if one of the following conditions is true:
1) No acknowledgment was sent for the previous segment received.
2) A segment is received, but no other segment arrives within 200 milliseconds for that connection.
Typically, an acknowledgment is sent for every other TCP segment that is received on a connection unless the delayed ACK timer (200 milliseconds) expires.
Disabling Delayed Acknowledgements can improve read latency and SAN performance.
The Windows implementation of TCP uses a registry key called TCPAckFrequency to adjust the delayed ACK timer.
Use these steps to adjust Delayed Acknowledgements, (send an ACK for every packet) in Windows on an iSCSI interface:
1. Start Registry Editor.
2. Locate and then click the following registry subkey:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\Interfaces\
Verify you have the correct interface by matching the ip address in the interface table.
3. On the Edit menu, point to New, and then click DWORD Value.
4. Name the new value TcpAckFrequency, and assign it a value of 1.
5. Quit Registry Editor.
6. Restart Windows for this change to take effect.
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WARNING: These steps are provided for information only. Tuning for performance can have undesired effects if you don't understand what you are doing so proceed with caution when making any changes.
For more information on Delayed Acknowledgements and Windows, go to: https://support.microsoft.com/kb/328890
