San presentation nov 2012 central pa


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Overview of Storage and SAN topics for DBAs. Presented to Central Pennsylvania SQL Server Users group on November 13, 2012.

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San presentation nov 2012 central pa

  1. 1. SAN Basics for DBAsJoey D’AntoniCentral Pennsylvania User GroupNovember 13, 2012
  2. 2. About Me Principal Architect SQL Server at Comcast Cable Blog: Twitter: @jdanton Email:
  3. 3. Storage Understanding Storage Types SSDs RAID Levels Components of a SAN SAN Benefits SANs and DR Summary
  4. 4. Storage
  5. 5. Different Kind of Storage
  6. 6. Hard Drive Components
  7. 7. Caching Almost all hard drives (SAN, Direct Attached) have some form of caching (RAM in front of storage) For SQL Servers—make sure you have a battery backed cache—if you don’t and power fails—you will lose data!
  8. 8. Disk Drives Hard Drives can only spin at 15,000 RPM. Hard Drive Performance has improved approximately 50x Have grown in capacity During the performance improvement CPU speed increase 5521x
  9. 9. Why is storage the bottleneck?
  10. 10. Memory versus Hard Drives
  11. 11. Latency ―Disk latency is around 13ms, but it depends on the quality and rotational speed of the hard drive. RAM latency is around 83 nanoseconds. How big is the difference? If RAM was an F-18 Hornet with a max speed of 1,190mph (more than 1.5x the speed of sound), disk accessspeed is a banana slug with a top speed of 0.007 mph.‖--credit Christian Paredes Blue Box Group
  12. 12. SSDs (Solid State Drives)
  13. 13. SSDs are Fast Much faster on random reads and writes  At least 5x better performance, often much more  Up to 350x faster on seeks Not nearly as much of difference on sequential reads and writes
  14. 14. SSDs are Expensive List Prices From Fusion-IO 160GB SLC ioDrive - $8495 320GB SLC ioDrive - $15495 320GB MLC ioDrive - $7495 640GB MLC ioDrive - $11495 320GB SLC ioDrive Duo – 16,990 640GB SLC ioDrive Duo - $30,990 640GB MLC ioDrive Duo - $14,990 1.28TB MLC ioDrive Duo - $22,990 These are really great for TempDB
  15. 15. SANs and SSDs More to come later!
  16. 16. RAID RAID—Redundant Array of Independent Disks Hard Drives Will Fail, RAID is what gives you protection from that
  17. 17. RAID 0
  18. 18. RAID 0, Don’t Do This From a major virtualization vendor benchmark
  19. 19. RAID 0 No data protection at all Best performance If you lose one disk, you lose it all As you add disks risk increases
  20. 20. RAID 1--Mirroring Mirroring No increase in write performance Read performance is increased 50% Capacity Loss
  21. 21. RAID 5—Striping (What you SAN Admin Wants) Maximum Capacity Big Write Penalty— gets worse as more disks are added Not good for highly transaction databases *Caveat
  22. 22. RAID 1+0 (10) Mirrored Striping Best performance Requires 4 or more drives Only 50% of actual capacity is used
  23. 23. Summary of RAID Levels Ask for RAID 10 for Everything (you won’t get it) Make sure your TempDB and Logs are on RAID 10 NEVER USE RAID 0!!!
  24. 24. Storage Area Network
  25. 25. What is a SAN? Basically a specialized computer for storage Computer, Switches and Hard Drives Not a performance device Can be used for redundancy and DR purposes Will serve many servers—so critical piece of your infrastructure
  26. 26. SAN Components HBA (Fibre) Card—Connects your server to SAN via Fiber Optic cable iSCSI Card—Ethernet Card connecting server to SAN Switch—Either fibre or ethernet switch connecting server to SAN SAN head unit—Controls processing, RAID levels Disk Array—The physical array behind your SAN (a bunch of hard drives)
  27. 27. SAN Terms LUN—Logical Unit Number, but in practical terms, what your SAN admin will call a disk that he presents to your server Fibre Channel—Cable connection to SAN IOPs—I/O Operations Per Second—the way your SAN admin measures performance
  28. 28. iSCSI vs Fibre Channel iSCSI is cheaper, and in smaller shops your network admin can manage the switches Over 10G Ethernet iSCSI is faster, unless…  16 GB FC is still uncommond Fiber is more susceptible to breakage, but currently more common Note—all SAN components must be the same speed, or network traffic reverts to slowest in chain
  29. 29. Multi-Pathing How your SAN admin sleeps at night! Make sure your databases servers are multi-pathed
  30. 30. SAN Throughput Max Mb/S 10 GB iSCSI 8 GB FC Max Mb/S 4 GB FC 1 GB iSCSI 0 200 400 600 800 1000 1200 1400
  31. 31. What are the Benefits of a SAN Expand Capacity easily and on the fly High availability Disaster Recovery
  32. 32. SANs and SQL Server—What to ask for TempDB absolutely needs its own disk (and you should have multiple TempDB files) Logs should be on a separate disk from data files Ideally separate system and user DBs If shared instance, put split high utilization DBs onto separate disk devices
  33. 33. SANs and DR—Block WARNING!—Don’t try this unless you have a real budget and a good SAN admin Most SANs vendors have as an option SAN replication Allows for multi-site failover Multi-site clustering fully supported in SQL Server 2012 Expensive—requires fiber connection between sites and expensive software
  34. 34. SAN Replication
  35. 35. Shared Environment vs DedicatedEnvironment
  36. 36. SANs are Multi-Tenant You don’t want to share disks with the Exchange server File servers are a decent partner for database servers But….
  37. 37. If you have are on a new SAN Most of the previous slides, don’t matter This technology on applies to really high end, enterprise-class storage arrays IBM, EMC, Hitachi
  38. 38. EMC VMax Fast DP Allows for dynamic moves of disk from faster to slower disks (Fibre channel to SATA), or slower to faster (FC to SSD) Totally dynamic, and seamless to servers Moves data in 768k extents Your SAN admin doesn’t know where your data is
  39. 39. FAST VPData SSD SSD SSD 15K Fibre Channel 15k Fibre Channel 15k Fibre Channel Log 10K SATA 10K SATA 10K SATA
  40. 40. What does this mean for the DBA? Overall—don’t worry too much about—the technology is solid Make sure your transaction logs are in a group that can not go to SSD. A lot of what we did in the past, changes with this technology
  41. 41. Test Your SAN Good free tools available like SQLIO Never run this on a production server (and warn your SAN admin)
  42. 42. Summary RAID 0 is bad Hard Drives will always be the bottleneck Be nice to your SAN admin—ask for RAID 10 Split your SQL files across many disks SSDs are fast, but pricey
  43. 43. Questions?
  44. 44. Platinum Sponsors:Gold Sponsors: Silver Sponsors: Bronze Sponsors: Swag Sponsors:
  45. 45. Contact Info Twitter: @jdanton Email: Blog (slides):