What will be the common reason in changing the instance numbers

[KVK]

ESL library connected to HP-UX box through SAN switch ..

previously tape device instance number were different . Now it has changed .

What will be common reasons behinf of changing the instance numbers ?

[RAC_1]

Did you change any of the ports on switch side?? This would cause devices changes. They are discovered by OS.

[KVK]

I am not pretty sure about switch side changes ...

In case there is switch port changes how the instance number will get changes without system reboot ?

[Steven E. Protter]

Shalom,

This commonly happens when there is a switch in hardware addressing.

The OS tracks what was and when it appears a new device has been added, creates a new instance number.

Also, it can be triggered by changes in back end configuration like LUNS on a SAN or EMC disk array.

SEP

[Sivakumar TS]

Dear KVK,

Whenever any change happens in the fabric the instance number also gets changed.

was there any change done?