VMware vSAN Deduplication and Compression Tips!
I’ve been getting some questions lately and here are a few quick thoughts on getting the most out of this feature.If you do not see deduplication or compression at all:
- See if the object space reservation policy has been set to above zero, as this reservation will effectively disable the benefits of deduplication for the virtual machine.
- Do not forget that swap is by default set to 100% but can be changed.
- If a legacy client or provisioning command is used that specifies “thick” or “Eager Zero Thick” this will override the OSR 100%. To fix this, you can reapply the policy. William Lam has a great blog post with some scripts on how to identify and resolve this.
- Make sure data is being written to the capacity tier. If you just provisioned 3-4 VM’s they may still be in the write buffer. We do not waste CPU or latency deduplicating or compressing data that may not have a long lifespan. If you only provisioned 10 VM’s that are 8GB each it’s quite possible that they have not destaged yet. If you are doing testing clone a lot of VM’s (I tend to create 200 or more) so you can force the destage to happen.
Performance anomalies (and why!) when testing vSAN’s deduplication and compression.
Read the entire article here, vSAN Deduplication and Compression Tips!
Via the fine folks at VMware!