After the CHAP certification is enabled on both the host and storage array, you are advised not to modify CHAP user information on the storage array. If you have to do so, see step 3.
1. After the host is rebooted, capture packets on the storage array. The following figure shows the CHAP information.
As shown in red boxes of the figure, the CHAP user name carried by the Login
Command of the host is test
, while the one observed on the storage array is root
. This is why the CHAP certification fails.
The packet capturing information shows that the host fails to be connected to the storage array (initiator failed to automatically recover the connection after the host is rebooted). This is because the host carried CHAP certification information differs from that on the storage array. Specifically, CHAP users are replaced on the storage array. However, the host uses the original CHAP users for certification after rebooted.
2. The same problem happens to EMC arrays.
As shown in the following figure, the EMC array is connected to the Windows Server 2008 host. When the CHAP certification is enabled, two links are normal.
Replace CHAP users on the storage array and reboot the host. The host fails to be connected to the EMC array, as shown in the following figure.
3. Finally, we have the solution: If you modify CHAP users on the storage array, you need to delete content in the red box as shown in the following figure. Then, rebuild the connection.
In this way, the connection is automatically recovered after the host is rebooted. Inside the red box is the negotiation content between the host initiator and storage array for reserving the CHAP certification information. If you only modify CHAP user information on the storage array without updating the negotiation content, the host will use the original CHAP certification information after rebooted, causing the certification to fail.