Dell Backup Compression and Storage Deduplication - a perfect match!
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Transcript of Dell Backup Compression and Storage Deduplication - a perfect match!
Backup Compression and Storage Deduplication: A perfect match?
Hosted by David Gugick &
David Swanson, Dell Software
June 27, 2013
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Agenda
• Speaker Introductions
• Deduplication Explained
• Deduplication and Backup Compression Benefits
• Ingest Rates
• Backup Recommendations
• Real-World Performance
• Takeaways
• Q & A
• Resources
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David Swanson
• Database Systems Consultant, Dell Software
David Gugick
• Product Management, Data Protection, Dell Software
• [email protected] com
• @davidgugick
Your Hosts
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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
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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
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Deduplication Benefits
• Storage is reduced
• Replication speeds improve
• Processing is moved from servers to storage
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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
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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
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• 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
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Backup Speed – 1 Backup
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Backup Speed – 2 Parallel Backups
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Backup Speed – 3 Parallel Backups
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Restore Speed
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Storage Footprint
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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
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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
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Q & A
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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
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Thanks