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1 SAN Basics for DBAs Joey DAntoni SQL Saturday #106 San Juan, PR

2 Complete the Evaluation Form to Win! Win a book – just for submitting your completed form. Each session evaluation form represents a chance to win. Pick up your evaluation form: In each presentation room Drop off your completed form: Near the exit of each presentation room

3 About Me Principal Architecture SQL Server at Comcast Blog: Twitter: @jdanton Email:

4 Storage Understanding Storage Types A little bit about SSDs RAID Levels Components of a SAN SAN Benefits SANs and DR Summary

5 Storage

6 Different Kind of Storage

7 Hard Drive Components

8 Caching Almost all hard drives (SAN, standalone) have some form of caching (RAM in front of storage) For SQL Serversmake sure you have a battery backed cacheif you dont and power failsyou will lose data!

9 Why is storage the bottleneck?

10 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

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 1,190 mph (more than 1.5x the speed of sound), disk access speed is a banana slug with a top speed of 0.007 mph.F-18 Hornetbanana slug --credit Christian Paredes Blue Box Group

12 CPU and Disks As CPUs have gotten faster they have the ability to drive more IOPs. Modern CPUs are so powerful they can saturate a 10 GB connection with I/O requestsyour disks cant possibly keep up

13 SSDs (Solid State Drives)

14 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

15 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

16 RAID RAIDRedundant Array of Independent Disks Hard Drives Will Fail, RAID is what gives you protection from that

17 RAID 0

18 RAID 0, Dont Do This From a major virtualization vendor benchmark

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 RAID 1--Mirroring Mirroring No increase in write performance Read performance is increased 50% Capacity Loss

21 RAID 5Striping (What you SAN Admin Wants) Maximum Capacity Big Write Penalty gets worse as more disks are added Not good for highly transaction databases BAARF

22 RAID 1+0 (10) Mirrored Striping Best performance Requires 4 or more drives Only 50% of actual capacity is used

23 Summary of RAID Levels Ask for RAID 10 for Everything (you wont get it) Make sure your TempDB and Logs are on RAID 10 NEVER USE RAID 0!!!

24 Storage Area Network

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 serversso critical piece of your infrastructure

26 SAN Components HBA (Fibre) CardConnects your server to SAN via Fiber Optic cable iSCSI CardEthernet Card connecting server to SAN SwitchEither fibre or ethernet switch connecting server to SAN SAN head unitControls processing, RAID levels Disk ArrayThe physical array behind your SAN (a bunch of hard drives)

27 iSCSI vs Fibre Channel iSCSI is cheaper, and in smaller shops your network admin can manage the switches Over 10G Ethernet iSCSI is faster, but that is still uncommon Fiber is more susceptible to breakage, but currently more common Fibre is faster, generally Noteall SAN components must be the same speed, or network traffic reverts to slowest in chain

28 Multi-Pathing How your SAN admin sleeps at night! Make sure your databases servers are multi-pathed

29 SAN Throughput

30 What are the Benefits of a SAN Expand Capacity easily and on the fly High availability Disaster Recovery

31 SAN Terms LUNLogical Unit Number, but in practical terms, what your SAN admin will call a disk that he presents to your server Fibre ChannelFiber Optic connection to SAN HBA CardCard that plugs into your server to connect it to the SAN IOPsI/O Operations Per Secondthe way your SAN admin measures performance

32 SANs and SQL ServerWhat 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 SANs and DRBlock WARNING!Dont 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 Expensiverequires fiber connection between sites and expensive software

34 SAN Replication

35 Shared Environment vs Dedicated Environment

36 SANs are Multi-Tenant You dont want to share disks with the Exchange server File servers are a decent partner for database servers But….

37 If you have are on a new SAN Most of the previous slides, dont matter This technology on applies to really high end, enterprise-class storage arrays IBM, EMC, Hitachi

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 doesnt know where your data is

39 What does this mean for the DBA? Overalldont worry too much aboutthe 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

40 Test Your SAN Good free tools available like SQLIO Never run this on a production server (and warn your SAN admin)

41 Summary RAID 0 is bad Hard Drives will always be the bottleneck Be nice to your SAN adminask for RAID 10 Split your SQL files across many disks SSDs are fast, but pricey

42 Questions?

43 Platinum Sponsors: Gold Sponsors: Silver Sponsors: Bronze Sponsors: Swag Sponsors:

44 Contact Info Twitter: @jdanton Email: Blog (slides):

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