You don’t have to sacrifice the things that simplify backup and recovery just because you introduce new technology. Take backup compression, for example. Maybe management has made an investment in storage de-duplication devices and now wants you to start using them for your SQL Server backups - and stop using backup compression. But is giving up backup compression really going to help management achieve its goals? Join us for a live webcast where we discuss how backup de-duplication works, the pros and cons of using backup compression, and how you can justify why you may not want to give up backup compression at all. Speaker - David Swanson and David Gugick If you are looking for the webcast recording, click here: http://bit.ly/1cc6jcC

1. Backup Compression and Storage
Deduplication: A perfect match?
Hosted by David Gugick &
David Swanson, Dell Software
June 27, 2013

2. 2
Agenda
• Speaker Introductions
• Deduplication Explained
• Deduplication and Backup Compression Benefits
• Ingest Rates
• Backup Recommendations
• Real-World Performance
• Takeaways
• Q & A
• Resources

3. 3
David Swanson
• Database Systems Consultant, Dell
Software
• david.swanson@software.dell.com
David Gugick
• Product Management, Data
Protection, Dell Software
• david.gugick@software.dell com
• @davidgugick
Your Hosts

4. 4
Deduplication Explained
• Eliminates the need to save duplicate data
• Connections
– CIFS, NFS, Proprietary (DD Boost, Dell RDA)
• Inline vs post-process
– Max ingest rate (single stream vs aggregate)
• Find matches
– Chunking – sliding windows / variable block
size
• Compress
• Target vs source-side deduplication
• Software vs hardware solutions
• Read Speed (Rehydration)
– Overhead varies by vendor
• Replication

5. 5
Deduplication Effectiveness Varies
• Variables that influence the dedupe ratio for a given workload include:
– The type of data being backed up: Not all data sets have the same amount of duplicate data or
compressibility
– The frequency of backups: More frequent backups will build the dedupe dictionary more quickly
– The retention period for backup jobs: Longer retention yields higher ratios
– The types of backups: Full backups will dedupe better than differential or transaction log backups
• Estimated deduplication ratio
– Ratio estimates range from 9-12:1 for databases – same as 90-92% compression
– Not a lot of duplicate data between databases
– Benefits with databases are largely due to chunk matches within a single database
• Retention recommendations
– Keep only what you need: Don’t keep more backups simply to raise the ratios
• Full or differential backups?
– Most vendors will estimate logical storage (dedupe ratios) based on whether the customer
performs full backups or leverages differential / incremental backups

6. 6
Deduplication Benefits
• Storage is reduced
• Replication speeds improve
• Processing is moved from servers to storage

7. 7
Backup Compression Benefits
• Reduces or eliminates disparity between source and target disk speeds
– Backup speeds improve
– Restore speeds improve
• Storage is reduced
• Network utilization is reduced
• Replication speeds improve
• Dump to and restore from tape speeds improve
• Helps with initializing Log Shipping / Mirroring / AlwaysOn Availability Groups

8. 8
Ingest Rates
• Max ingest rate determines how fast the device can consume data
– Many times stats are based on multiple backup streams
– Single stream performance may be lower
– Varies widely by how much you spend
• Network plays an important part
– In practice, limits are lower
– 1 Gb = 125 MB / Sec
– 10 Gb = 1.25 GB / Sec
– Fibre Channel (8 GFC) = 1.6 GB / Sec

9. 9
• Offset backups to avoid network
and ingest rate contention
• Test with and without compression
– Try a low-CPU compressor
– 85% compression gives you close
to 7X the write bandwidth
• Consider using differential
backups to reduce storage and
backup time
– 70% reduction in data backed up
means backups run on average
3.3X faster
Backup Recommendations

10. 10
Backup Speed – 1 Backup

11. 11
Backup Speed – 2 Parallel Backups

12. 12
Backup Speed – 3 Parallel Backups

13. 13
Restore Speed

14. 14
Storage Footprint

15. 15
Takeaways
• Backup compression and deduplication are a good match
• Test your environment
– Your results will vary based on many factors including: Rated speed of appliance, network
design, backup job coordination, compressibility of the database, database data change
rate
– Don’t expect much deduplication between different databases – most of the benefits are
gained from backups of the same database
• Deduplication storage appliances are almost always shared in an environment
– A single test on a single database in the lab is not representative of production
– Furthermore, running full backups on the same database 30 times in a row as a test is not
representative of production either
– Even with exclusive access to deduplication storage by DBA team, there will usually be
contention from parallel backup streams
• You won’t know the full effect of performing uncompressed backups until you test
– Maintenance windows and RTOs may be affected

16. 16
Takeaways
• Test using lightweight backup compression
– Avoids CPU load on the database server
– Allows the deduplication storage the opportunity for some extra dedupe
– Avoid Adaptive Compression to maximize deduplication
• If backup and restore times are most important, don’t be concerned with actual
storage consumed
– At worst, it’s a wash. At best, you’re saving space with compression
– Don’t be overly concerned with final deduplication ratios - don’t keep 30 days of backups
for each db just to get better deduplication ratios if you only need 14 days
• Consider reducing data backed up using differential backups
– Reduces the data read from SQL Server, sent over the network, and processed by the
storage
– Reduced backup windows
– Can be compressed just the same

17. 17
Q & A

18. 18
Resources - References
• Some Deduplication Resources
– Demystifying Deduplication White Paper: http://i.dell.com/sites/doccontent/shared-
content/data-sheets/en/Documents/demystifying-deduplication.pdf
– Why Dedupe is a Bad Idea for SQL Server Backups:
http://www.brentozar.com/archive/2009/11/why-dedupe-is-a-bad-idea-for-sql-server-
backups/
– Backup Compression and Deduplication blog posts:
http://communities.quest.com/community/data-protection/blog/2012/04/05/backup-
compression-and-deduplication-good-or-bad
• LiteSpeed
– LiteSpeed Landing Page: http://www.quest.com/litespeed-for-sql-server/
– Tech Brief: Top 7 LiteSpeed Features DBAs Should Know About:
http://www.quest.com/techbrief/top-6-litespeed-features-dbas-should-know-
about815805.aspx
– Webcasts and Events: http://www.quest.com/events/list.aspx?contenttypeid=15&prod=192
• Dell DR4100
– http://www.dell.com/us/business/p/dell-dr4100/pd

19. 19
Thanks