Dealing with SSWS

Replication and Disaster Recovery Administration Guide for Hitachi NAS Platform

Version
15.1.x
Audience
anonymous
Part Number
MK-92HNAS009-29

If production SDs are lost, recovery of the data on the backup SDs can leave them as S-Vols and put the mirror relationship into a state called SSWS. Uniquely, SSWS causes the S-Vols to become writable. But the server is unable to detect this state, and treats the S-Vols as secondary SDs in the usual way, refusing to perform I/O to them.

For the duration of the SSWS state, use the sd-peg command to override the SDs' normally-determined roles and make the NAS server treat S-Vols as primary SDs. Be sure to remove the peg using the sd-peg --default-role command as soon as the SSWS state ends. In all states not involving SSWS, the server must be allowed to detect SDs' mirror roles for itself.