HPE EVA Storage

CA async replication issue

 
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Anoopkumar
Frequent Advisor

CA async replication issue

Hi Support,
Recently I did make some DR group to asyncmode after this activity I could see in EVA storage space is drastically reduced. So I did a testing with 250GB vdisk.

1. When I create DR group in sync mode am not facing any issues.
2. When I select async mode , around 600 GB is reserving in EVA.
3. Tried to put back in Sync mode again , But this action didn’t release the space.
4. Manually deleted the DR group then its released the space.

I gone thru the documents but nowhere its mention about the space reservation. As per my knowledge its demand allocated..
please help me to find more details about it..

Thanks
Anoop

 

 

P.S. This thread has been moved from General to Storage Area Networks (SAN) (Enterprise). - Hp Forum Moderator

5 REPLIES 5
Víctor Cespón
Honored Contributor

Re: CA async replication issue

In asynchronous replication a replication log is created to store the data that has not been copied to the destination array yet.

The size of this log can be changed, look in the DR group properties. The minimum and default values are detailed on the EVA compatibility tables:

http://bizsupport1.austin.hp.com/bc/docs/support/SupportManual/c02010760/c02010760.pdf

Page 32
Anoopkumar
Frequent Advisor

Re: CA async replication issue

Hi vcespon ,

Thanks for the replay
But there is no logging happening,But it shoudnt reserv that space rt? if it reserves also after changing back to sync mode should release space.Please correct me if am wrong.
Víctor Cespón
Honored Contributor
Solution

Re: CA async replication issue

For recent firmware versions, minimum log size is 5 GB and default is 100 GB (taking double that space since it's stored on RAID 1).

The disk space is reserved even if nothing is logged, and it's not freed if the DR Group is switched to synchronous mode.

Log Size :

When a DR group is in a logging state, the log is allocated on demand, and will be allocated up to the maximum log size. The maximum size log size for all modes is 2TB. The minimum size of a log is 136MB for synchronous and standard asynchronous modes, and 1624MB for enhanced asynchronous mode. The default size for logs on the EVA4400 is 5GB for 09000000, 09001000 and 100GB for the EVA4400 XCS 09003000 and later. The default size for logs on the EVA6400/8400 running XCS 09500000 is 100GB.

Once set, the space is reserved for the DR group write history log and cannot be reduced in size without first transitioning to synchronous mode and allowing the log to drain.
Anoopkumar
Frequent Advisor

Re: CA async replication issue

Thanks for the replay ,

Now its clear to me .

If I delete the DR group its relasing the space and for sync mode just couple of GBs reserving.Thanks for the valid info..

Anoop
Anoopkumar
Frequent Advisor

Re: CA async replication issue

Thanks