EVA 4400 failover and then failback

[Magnus Appelgren]

We are gonna test our Business Continousy Plan. EVA's are in different locations connected with 2g ISL's. My questions is what happens when we failback, will that trigger full copys? We are talking about 10tb data so that will take to long if it will be full copy...

Regards
Magnus

[Víctor Cespón · Accepted solution]

A full copy will not be initiated unless the log disk is invalidated.
This can happen when it reachs maximum size or there's no more space left on the disk group.

If the failover is done manually (after setting all DR groups in synchronous mode) and the links are UP, there should not be any data loss, since all I/Os have been done on both EVAs. We are just changing the source and target disks.

[Uwe Zessin]

So far I have not seen full copies during tests as long as there was enough free space in the disk group(s) for the WHL (write history log).

[Magnus Appelgren]

Thx for your replies.

Just to clarify, I'm gonna power off prod EVA, do failover on backup EVA, present to new hosts etc. Then we will try all servers and applications etc. When we are done I'll do failover(failback) on prod EVA. In my DR groups log size is the default 102,4 mb, what happens when that is full? Do i need to change anything to prevent full copy? DR groups are in synchronous mode.

[Magnus Appelgren]

bump!