Joseph Dantoni presentation on Virtualization from SQL Saturday DC.

1. Virtualization for DBAs
Joey D’Antoni
November 5, 2011

2. About Me
 Senior SQL Server DBA at Comcast
 Blog: joedantoni.wordpress.com
 Twitter @jdanton
 Email jdanton1@yahoo.com
11/7/2011
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3. Virtualization
 Major Players
 Terms
 Costs and Benefits
 Technology
 Optimizing SQL for a Virtual Environment
 Summary

4. Major Virtualization Players

5. It seemed like a good idea at the time…

6. Server Room Sprawl
 Server sprawl
 SQL sprawl
 Power and Cooling Issues in DCs
 Broader availability of SAN storage

7. Terminology
 Guest—The virtual server running
underneath the physical host and hypervisor
(instance of an Operating System)
 Host—The physical server that your virtual
machines run on
 Hypervisor—The underlying software that
performs the load balancing and sharing of
resources between guest operating systems

8. Terminology (cont’d)
 Thin Provisioning—Allowance in virtual
environments to overallocate physical
resources (more to come later)
 Deduplication—Process of compressing
memory/disk space by saving only one copy
of common bits
 vMotion/LiveMigration—Process which
moves guest OS’s from host with high
resource utilization to lower. Also an HA
function with the hypervisor

9. Terminology (cont’d)
 Snapshot—A full point in time backup of your
guest OS (very handy for
upgrades/patches/code releases)
 Cloning—The process of building a gold
guest image in order to rapid deployment

10. Costs
 VMWare isn’t cheap
 Licensing about $25k per server for a Enterprise
plus on a decent sized server
 Licensing changed from CPU—to CPU with
memory grants, allowed 96 GB per CPU license
 Hyper-V
 Included with your Windows Server Licenses
(amount of VMs vary based on edition)
 SCOM, while not required is recommended

11. Benefits of Virtualization
 Lower cooling and power
 Higher utilization of hardware
 Can be used for HA configurations
 Rapid Deployment of new environments
 Use Gold Standard servers and rollout
 Snapshots

12. How this works…
Host
One Physical Server
Hypervisor
Guest Guest Guest

13. What does the hypervisor do?
 Manages resources between guest O/S
 Memory management
 Backups
 Failover and DR

14. VMWare Architecture

15. Snapshots

16. HA and DR

17. Typical Hardware
 Virtualization hosts are the typical servers
you might run SQL Server on.
 2 x 4-6 core processors (Dual socket servers
represent 80% of install base)
 A Lot of RAM

18. Thin Provisioning
 Allows over allocation
of resources
 Increases storage
provisioning
 Management console
allows for easy
management of this
along with SAN
 NOT GOOD FOR
PRODUCTION DB
SERVERS!!!

19. Shared Environment vs Dedicated
Environment

20. Multi-Tenant Environments
 This can make monitoring and baselining
your server more challenging
 You will want to have open communications
with your VM administrators
 Ask for view access into VCenter—it will
show you what else is going on in the
environment

21. CPUs
 Can be over allocated
 Use servers with the newest chips—they are
optimized for Virtual Workloads
 Maintain 1:1 ratio of physical cores to vCPU
for production boxes
 For production workloads you may want to
dedicate CPUs to the machine

22. Memory Management
 Memory can be
over allocated (but
don’t do it for
production!!!)
 Hypervisor handles
it by de-duplicating
memory.
 Host Page Files

23. Balloon Driver

24. Balloon Driver
 When hosts
comes under
memory pressure,
VMWare reclaims
memory from
guests

25. Storage

26. I/O Concerns
 Two choices of file types—VMFS (VMWare
File System) and RDM (Raw Device
Mapping)
 Performance between two is similar
 RDM is required for clustering
 VMFS generally more flexible
 Use Shared Storage (SAN) to get HA and DR
functionality

27. I/O Concerns
 Partition alignments still matters < Windows
2008
 Work with storage team to monitor I/O—
Hypervisors can have strange I/O patterns

28. Virtual Server

29. Virtualizing SQL Server
 Use Trace Flag –T834—large pages enabled
 Set min and max memory—this will lock
SQL’s memory to prevent possible balloon
driver impact
 Follow the same storage best practices you
would for a physical box (Separate TempDB,
Data, Logs)
 Test out I/O performance before beginning

30. Monitoring SQL Server
 From the server perspective everything stays
the same
 Everything may not match at times
 Ask for access to the vSphere client!
 It’s the only way to have an overview into the
broader system

31. Performance Issues
 Troubleshoot as you normally would, then
check VMWare
 Similarly with a SAN—try to identify what you
apps are sharing your resources
 Can adjust load on the fly by using vMotion
(or Live Migration)

32. Summary
 Virtualization is the future, and the future is
now!
 Virtual servers work from a shared resource
pool and that can impact your workloads
 Identify changes you need to make to your
SQL Servers for Virtual Environments
 Get access to your virtualization
management layer

33. Questions?

34. Contact Info
 Twitter: @jdanton
 Email: jdanton1@yahoo.com
 Blog (slides): joedantoni.wordpress.com