Data Backup and Recovery

Storage efficiency between source and vault destiantion volume


Hi Pro’s!

I am confused regarding source and destination storage efficiency. What is best practice?
In my case, we have server data volumes nfs mounted in vmware. These volumes have:

Compression: true
Inline Compression: true
Constituent Volume: false
Inline Dedupe: true
Data Compaction: true
Cross Volume Inline Deduplication: true
Cross Volume Background Deduplication: true

The total savings are 33% (dedupe 10%, compression 23%)

Snapshot retention is 10 days

The primary volume above is setup to snapmirror its data to a vault volume once every night and store its snapshots for 90 days.

The secondary has no storage efficiency turned on at all.

I want to save as much storage as possible.

Will my primary storage system dedupe/compress all data in both primary and secondary storage, even if the snapshot retentions are different or will it only dedupe/compress data in my primary system?






if you do not set compression, compaction and vol-dedup on the DST, they by default retained as-is on the DST regardless for your snapshot policies (that's given that the baseline was initiated after they all run and completed on the SRC).


As for AGGR level dedup, that's not saved (and also not supported for HDD systems). But I don't really know if you can run it separately on the DST (seems that you can on DPO systems, but that's the only place I've seen it mentioned).




"Both compression and deduplication are supported with volume SnapMirror.Volume SnapMirror operates at the physical block level. Thus, when deduplication is enabled on the source, the data sent over the wire for replication remains deduplicated, and the savings are inherited at the destination. For compression, storage efficiency is preserved or lost during replication,depending on the following configuration:

Source and destination volumes use the same compression type (either adaptive or secondary):

Logical replication with storage efficiency is used.Storage efficiency (compressed and deduplicated blocks) is preserved during data transfer"


"Regardless of whether the source system supports data compaction, the data on the destination is compacted on the data compaction supported destination system."




"If you require compression savings on the destination and your source has compression enabled, then do not enable compression on the SnapVault destination. The savings are already inherited on the destination"



"As a best practice, if deduplication is enabled on the source, enable only deduplication on the SnapVault destination if you expect SnapVault updates to occur from Snapshot copies created before deduplication completes on the source. "


"Regardless of whether the source system supports data compaction, the data on the destination is compacted on the data compaction supported destination system."


Gidi Marcus (Linkedin) - Storage and Microsoft technologies consultant - Hydro IT LTD - UK


Hi and thank you for your reply. Sorry my late reply... been off work for some time


Regarding Snapvault and dedupe...

  1. Is it correct that dedupe on destination volume shall be 'false ' if I have the below times for my volume:
    -Lets say my primary snapshot goes off at 03am
    -My primary storage efficiency starts at 04am and finish before 05am
    -My snapvault update  (snapmirror schedule) starts at 06am

  2. And another question regarding dedupe on destination:
    If the above is correct and I have 10 daily snapshots on my primary system and 90 snapshots on my destination system, will all the 90 snapshots on the destination system be included in the deduplication or only 10 ?
    Which storage system own the dedupe for my destination system volume? The primary or the secondary (destination)