Hi All,
I am using EMC VNX, backup storage are DD and HP D3600 (MSDP). I found that the deduplication ratio is very pool which compared with NDMP backup to DD and D3600.
Is it normal for MSDP keep EMC NDMP data? Pls. advise, many thanks.
Regards,
Ken
Hi Ken
As you have discovered NDMP backups to MSDP by default do not dedupe particularly well for NAS filers that do not have NetBackup stream handlers (such as NetApp). The reason is the default behavious for MSDP is to use a fixed block size when "chunking" the data.
All is not lost though, there is a feature called VLD (variable length deduplication) whichyou can enable on the MSDP. With this set you should get similar deduplication rates as the DD.
I refer you to two links - one a previous answer in VOX from Anshu_Pathak https://vox.veritas.com/t5/NetBackup/MSDP-Variable-Length-Deduplication/td-p/863204
These should help resolve your poor dedupe rates.
Regards
D.
Hi David,
Is there no way to increase the dedup ratio of existing backup image in HP D3600 ?
And If the NDMP image is copied from DD to MSDP, enable VLD is for not function well, right?
(due to DD is almost full, I copy the NDMP images to D3600 for offload the usage)
Regards,
Ken
There is no way to change the existing dedupe ratio of backups already in the MSDP storage.
Using VLD will only help with new backups. Make sure you read the FAQs and also refer to the NetBackup Deduplication Guide, in particular the section "About variable-length deduplication on NetBackup clients".
