In a complex database environment, keeping tabs on the health and stability of each system is critical to ensure data availability, accessibility, recoverability, and security. Through performing thousands of health checks for clients, Datavail has identified the top 10 issues affecting SQL Server performance. From misconfigured memory settings to missing backups, Datavail has gathered evidence from client health check history that identifies the most common issues DBA managers must correct for optimal database performance. Datavail’s SQL Health Check is used not only as a diagnostic tool but also a road map of the work that needs to be performed. From there, routine health checks have proven to improve database performance. SQL Server Senior DBA for Datavail Andy McDermid will share the top 10 issues, the consequences of not taking action, and why consistent use of a SQL Server Health Check in conjunction with ongoing database management can lead to improved database environments and maximize the investment of time and resources.

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About Your Presenter
Andy McDermid, SQL Server DBA, Datavail
Andy is a MCITP certified MS SQL DBA who delivers and manages
delivery of DBA services to many diverse clients. He enjoys
helping his clients by finding and deploying pragmatic and
practical solutions for their database issues. Andy is always
working to improve and expand his DBA skills and he likes to
share the experience via writing. You can read more about his
work here http://andrewmcdermid.net.

2. How Regular SQL Health Checks
Keep Your Database in Shape
Andy McDermid
SQL Server DBA, Datavail
Andy.mcdermid@datavail.com
NWOSSUG, Toledo

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Your Chance To Win!
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About Me
Andy McDermid
• Broomfield, CO
• Principal SQL DBA at Datavail
Blog: http://www.datavail.com/blog |
Twitter: @oldskipole

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About Datavail
Datavail is a managed service provider for databases
• OracleDB2
• MySQL
• MS SQL
• Oracle & Oracle EBS
• No SQL
24x7x365 Coverage
• U.S.-based DBA team
• Offshore team
Datavail DBAs work with many SQL servers Health Checks
used to expose the issues
Recurring health checks keep servers up to standards
Frees up time so you can be more strategic

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About This Presentation
SQL Health Checks
• Achieve and maintain a standard of health for each
instance
The most common misconfigurations and set up issues
• After thousands of health checks for many servers, these
are the top issues
• Review the function
• What is the default and is it appropriate?
• What might be the best settings to work towards a
standard configuration
* These are best practices and you should make the best decision for
your specific environment.

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Three Parts of This Presentation
1. Easy Picking
Server and database configurations, backups
2. Best Bang
Server configuration, index topics
3. Long Road
DB file location, size and growth, tempdb
configuration

8. Easy Picking

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Server Configuration (sp_configure options)
Priority boost
• Sets the SQL service to run at the highest priority -13
• Default is 0 – which is priority of 7
• May starve other processes – network and OS
• Depreciated

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Server Configuration (sp_configure options)
Recovery Interval
• Approximately how long to recover database after a restart
or crash
• Default setting is 0 which means ~ 1 minute recovery time
• Affects checkpoint frequency so may be adjusted to reduce
IO spikes

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CPU affinity mask
• Designates a set of logical CPU to an instance
• Default is 0 – no specific association
• Typical use case – stacked instances
• Three methods to change
– SQL Server Management Studio
– sp_configure ‘affinity mask’ (and ‘affinity64 mask’ if >64
CPU)
– ALTER SERVER CONFIGURATION SET PROCESS AFFINITY
• Avoid hard binding – enable trace flag 8002
Server Configuration (sp_configure options)

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Database Options
Auto close
• DB ‘closes’ when there are no users connections
• Default is disabled
• Databases migrated from SQL 2000 MSDE
• Unnecessary overhead, depreciated
Auto shrink
• Free DB space automatically returned to OS
• Default is disabled
• Always … no wait … never a good idea
• Causes fragmentation
• Manage file size and growth manually

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Page verify
• Checks page for corruption on each read
• Default is CHECKSUM but databases migrated from older
versions may be using Torn Page Detection, None
• CHECKSUM vs Torn Page Detection
• CHECKSUM – the more complete option
Database Options

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Backups
Missing
• Missing full backups
• Missing transaction log backups
Misconfigured
• Destination
• Low or no retention days
Failing
• Reduce duration with Striped files or BUFFERCOUNT
• Plan to accommodate X days and account for growth

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Policy Based Management
Easy method to keep an instance up to standard
1. Define configuration ‘template’
2. Build it as a set of policies
3. Evaluate regularly (e.g. monthly checkups)

16. Best Bang

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Server Configuration (sp_configure options)
Maximum Memory
• Default is 2147483647
• Sets the buffer pool size (includes plan cache)
• Reserve for OS - rule of thumb
– 1 GB of RAM for the OS
– 1 GB for each 4 GB of RAM installed from 4–16 GB,
– 1 GB for every 8 GB RAM installed above 16 GB
RAM
Minimum Memory
• Dedicated instance- consider setting Min = Max

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Memory Pressure
• If Target Server Memory depressed below Maximum
Memory = external pressure
• If Total Server Memory depressed below Target Server
Memory = internal pressure
Server Configuration (sp_configure options)

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Max Degree of Parallelism
• Default is 0 – as many degrees as logical CPU
• May not be optimal for instances with many CPUs
• Microsoft recommends a per NUMA node calculation:
CPU/NUMA node
– E.g. 16 CPU with 4 NUMA nodes = MDOP 4
Server Configuration (sp_configure options)

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Cost Threshold for Parallelism
– Controls when a plan goes parallel
– Default is 5 (query cost)
– Query the plan cache for typical query costs and set
CTFP accordingly
Server Configuration (sp_configure options)

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Baselines
Adjust SQL Server for maximum throughput
1. Configure instance to best practice
2. Gather baseline metrics
3. Evaluate
4. Tweak as necessary
5. Repeat

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Index fragmentation
• Maintenance plans
• Custom scripts to
– Ignore unused low page count, low fragmentation
– Threshold to reorganize or rebuild
– Maximum duration
Out of date statistics
• Maintenance plans
• Custom scripts
Indexes

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Indexes
Duplicate, overlapping, and unused Indexes
• Drop or disable
• Impacts of index sprawl
– Database size on disk
– Wasted buffer pool
– Transaction log
Missing indexes
• Easy to find, easy to fix
• Careful… but not too careful

24. Long Road

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System and user database files on same disk
• DR concern
Data and log files on same disk
• IO profile of Data and Log files
San or VM or both
• Does it even matter? Organizationally, yes.
Database Files

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File growth too low
• Default is 1MB data file
• May result in continuous growth
• External file fragmentation
• Set growth and size appropriately, enable instant file
initialization
File growth in percent
• Default is 10% for log files
• Large file results in large grows
• Small files results in small grows (many VLFs)
• Set growth and size appropriately
Database Files

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Database Files
High VLF count
• Log file fragmentation
• Log growth creates VLFs
– chunks less than 64MB and up to 64MB = 4 VLFs
– chunks larger than 64MB and up to 1GB = 8 VLFs
– chunks larger than 1GB = 16 VLFs
• Slow recovery times - restores, reboots, failovers, ect
• Rule of thumb – 512MB per VLF

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Reducing VLFs
1. Before you shrink the log file take note of the current size in
MB – assuming this is the correct size –or whatever your new
size is
2. Shrink, backup, repeat as necessary to minimize VLFs. Works
best in a time of quiet so the log can clear easily – if there are
many many vlfs, if not you may need to make quite a few
transaction log backups between shrinks since the shrink clears
unused VLF blocks.
3. Divide 8000MB into the original size, round up, grow the
log back that many times in multiples of 8000MB.
Database Files

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Temp DB Files
• Default is one file and one log file
• GAMSGAM contention
• Trace Flag 1118
• Rule of thumb – multiple files
– 1 per core up to 8,
– then add 4 more at a time up to logical CPU

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Datavail Health Check
Based on PBM style pass/fail evaluation
Includes everything we discussed here and many more
Easy to read summary page
Comprehensive detail pages
Compliance per category
Customizable
Automated

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Questions?
For a copy of today’s presentation email
Andrea.Crosby@Datavail.com