Very Small shootout: DeDuplication (NetApp) vs. Compression (vRanger Pro)
The purpose of this shootout was to analyze already backed up images of VM guests sitting idle on disk. We like to keep 7 days online, so I was curious as to how the two compared in our environment.
Compressed vs Deduplicated
COMPRESSED: (backed up via vRanger Pro over VCB, size on win NTFS volume)
citrix_server = 4.29gb
win_sql_server_64bit = 9.76gb
citrix_server2 = 6.14gb
win2k3_member = 4.97gb
compressed vm total = 25.16gb
UNCOMPRESSED:
citrix_server = 10gb
win_sql_server_64bit = 20gb
citrix_server2 = 10gb
win2k3_member = 35gb
uncompressed total = 75gb
DEDUPED VS COMPRESSED:
deduped = 54.29% savings (NetApp cmd output below)
compressed = 66.45% savings
Here’s the actual output from the NetApp find_space exe:
A-SIS Deduplication Space Savings estimate.
Name of Fingerprint File: d:\esx_deduped.txt
Total Number of Directories: 5
Total Number of Files: 58
Total Number of 4K Blocks: 19662390
Total Number of Duplicate Blocks: 10673928
Percentage of Duplicate Data: 54.29
Scan Start Time: Wed, Jul 30 2008 3:40:16 PM
Scan End Time: Wed, Jul 30 2008 4:22:25 PM
I’ll be honest, I was expecting deduplication to blow compression out of the water even with only 4 vm’s. I’ll go out on a limb and venture that deduplication would provide more results as you toss more vm’s into the picture.
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The benefits of de-duplication will be more evident as the dedupe target sees the data over and over through the backup process. The best combination would be to use a Netapp volume that has A-SIS enabled as the target for the vRanger backups, then I think you’d really start to see some compression numbers. This is how other de-dupe vendors advertise 20:1 compression ratios.
I definitely agree with you about the more data thrown into deduplication the better the results will be. From my testing I was unable to get A-SIS to deduplicate compressed archives; so vRanger must be used with the -nozip option for A-SIS to work correctly.
This should not be so surprising. ,
Great post. I ran across this a bit back and wanted to look into the compression setting with backup exec and dedup as well as try to address the multiple backups of the same data. I ended up doing a somewhat similar test to yours though and posted the results here: http://danstechnotes.blogspot.com/2009/11/netapp-and-backup-exec-compression-vs.html
Figured I’d share the link.
Thanks!