We have a Centera (EMC Centera Gen4) replication set in our production environment. We 're going for a code upgrade ..I 've two questions:

1) Now , we already have a disk failure in one of the nodes and an internal switch failure . My question is what is the risk when another disk failes ?  I know , it depends on which disk has failed,but,  if i 've to know what  disk failure ( if  second disk has to fail) can risk the primary cluster?

Basically , i 'm looking for what can jeopardize the Objects(data) in this scenario.

2) Also, What can be the backput plan set up when something goes bad.I understand , doing Code upgrade doesn't call for an outage. Just in case.

What should be my make out plan if the primary cluster goes down during code upgrade?

3) what are PEA files? what 's the use of it?

4)what is the consequence of replication being stopped, i see , repication from target to primary cluster is "on", however.

Data is stored with mirror protection

I will very much appreciate if some one can shed some light on this.

Thanks in anticipation!