The I/O Timeout can prevent the disk I/O response delay.
If an error occurs to the disk device or I/O path hardware, the device driver and hardware will repeat the retry process, and the I/O response may become delayed. If the system disk's I/O response has become delayed, the continuation of transactions will be interfered with the slowdown of the entire system.
If using the GDS and mirroring the device, and an error has occurred on one disk device, the device driver's retry process will be reduced. The disk device for which an error occurred will be disconnected from mirroring at an early stage and, so that responses can come from the normally operating disk devices, the I/O response delay will be reduced.
When Solaris 11 is used, this function will be enabled by registering the system disk with GDS even though the ZFS mirroring function is used to make the system disk redundant.
Figure 1.14 I/O response during normal operation
Figure 1.15 I/O response delay during a disk error
Figure 1.16 Suppression of an I/O response delay during a disk error
GDS: Global Disk Services
Note
This function is enabled for the internal disk and Expansion File Unit. However, this function is not enabled for the disk array unit.
For the disk where a concatenation function or a striping function is used, this function will not be enabled.
