VSan Storage Policies Exchange DAGs

[r1819m2]

Looking to change the from the default storage policy over to another storage policy that has compression and dedup enabled on both exchange servers configured in DAGs. doing this one at a time during production hours will this cause any known issues? Can't seem to find any information online I don't think it will but seeing if anyone else had any experience with it. Thanks.

[GreatWhiteTec]

Hi r1819m2,

At the moment, deduplication and compression in vSAN is done at the cluster level. Both are turn off/on at the cluster level for the entire vSAN Datastore. Although you can have a storage policy with FTT=0 (since DAGs replicate Exchange), there is no guarantee that the objects/components will land on different DGs/Hosts. At the moment there is no "Data pinning" feature for scenarios like this...

Hope that helps.

[r1819m2]

Hello, I have the Exchange servers on the default Vsan storage policy now. I do need to move those two servers storage policy to the erasure coding policy. I thought dedup and compression was also configured at the policy level but now i believe i was mistaken. So, still confused if changing the storage policy on Exchange DAG servers will create any issues with corruption or replication issues.

[GreatWhiteTec · Accepted solution]

So the default policy is FTT=1 with RAID1 Mirroring (performance). Assigning a policy using EC RAID5 or RAID6 to the exchange servers may help with some space savings, but there is a write penalty. Changing the policy shouldn't have any effect on corruption or replication, but keep in mind that when you go from RAID1 to RAID5 for example, those object have to be rebuilt before the old ones can be deleted (protects from failure), so you will need sufficient space to do this. Changing from RAID1 to EC is a decision you will have to make based on workload, and space.

Here is an example of what happens when you change policy Storage and Availability Technical Documents