There are two modes in I/O preference mode when remote path failed. According to the selected mode, an I/O operation from the server is specified for a GAD pair that is suspended due to a remote path failure.
- Disabled (default)
- An I/O from the server continues on a volume on the storage system that has received an I/O from the server. If an I/O from the server has been received on both the primary and secondary storage systems, the I/O from the server continues only on a volume on either of the storage systems.
- Primary Volume
- An I/O from the server preferentially continues on a P-VOL.
Note:
- When no volume is set for the quorum disk, an I/O from the server can continue on a P-VOL regardless of setting I/O preference mode when remote path failed.
- A different I/O preference mode when remote path failed cannot be set for a GAD pair in the same consistency group.
- If a failure occurs in a location other than a remote path (for example, the storage system failure), an I/O from the server might continue on an S-VOL even if I/O preference mode when remote path failed is set to Primary Volume.
CAUTION:
When I/O preference mode when remote path failed is set to Primary Volume, if a failure that prevents an access to a P-VOL (for example, a path failure from the server to the P-VOL) occurs at the same time, the access might be lost.
For information about setting I/O preference mode when the remote path failed, see the following topics.
- Setting I/O preference mode when remote path failed and creating a new pair using VSM auto-configuration:
Creating a GAD pair with I/O preference mode when remote path failed
- Changing the setting of I/O preference mode when remote path failed for an existing pair:
Changing I/O preference mode when remote path failed for an existing pair