When you perform Asymmetric Logical Unit Access (ALUA) in a cross-path configuration, you can specify the preferred path to use for issuing an I/O request from a server to a storage system.
To specify the preferred path, you must enable the ALUA mode in the storage system, and use the asymmetric access status setting to set the path to use as the preferred path. The ALUA mode setting enables the server to manage the preferred path to which the server issues an I/O request by recognizing the volume on the storage system. The server can also manage the changes in the asymmetric access status and the switching of a path to which the server issues an I/O request.
You should be aware of how the server behaves if you change ALUA settings after the server recognizes those settings or if those changes are made while the server is online.
- If you change the ALUA settings for a volume that the server has already recognized, shut down the server before changing the ALUA settings. After changing the settings, start the server, and then enable the server to recognize the volume. The server can recognize the changes in the ALUA settings.
- If you change the ALUA settings while the server is online, the server might not recognize the changes in the ALUA settings or might perform abnormally.
Note: When the preferred and nonpreferred paths
using ALUA is set, set I/O preference mode when remote path failed for a GAD pair to Primary
Volume. For more information, see I/O preference mode when remote path failed in a GAD
pair.