1. Establishing a Service Level Agreement SLA
=tg= Thomas Grohser, NTT DATA
SQL Server MVP
SQL Server Performance Engineering
Silicon Valley, CA 4/9/2016

2. select * from =tg= where topic =
Remark
SQL 4.21
First SQL Server ever used (1994)
SQL 6.0
First Log Shipping with failover
SQL 6.5
First SQL Server Cluster (NT4.0 + Wolfpack)
SQL 7.0
2+ billion rows / month in a single Table
SQL 2000
938 days with 100% availability
SQL 2000 IA64
First SQL Server on Itanium IA64
SQL 2005 IA64
First OLTP long distance database mirroring
SQL 2008 IA64
First Replication into mirrored databases
SQL 2008R2 IA64
SQL 2008R2 x64
First 256 CPUs & > STMT/sec
First Scale out > STMT/sec
First time 1.2+ trillion rows in a table
SQL 2012
Transactions per second
1.2 Trillion Rows in a table
SQL 2014
Transactions per second
Fully automated deploy and management
SQL Next
NDA
20 Years with SQL Server
=tg= Thomas Grohser,
NTT DATA
Focus on SQL Server Security,
Performance Engineering,
Infrastructure and Architecture
New Tool coming in 2015
Close Relationship with
SQLCAT (SQL Server Customer Advisory Team)
SCAN (SQL Server Customer Advisory Network)
TAP (Technology Adoption Program)
Product Teams in Redmond
Active PASS member and
PASS Summit Speaker

3. NTT DATA Overview Why NTT DATA for MS Services:
20,000 professionals – Optimizing balanced global delivery
$1.6B – Annual revenues with history of above-market growth
Long-term relationships – >1,000 clients; mid-market to large enterprise
Delivery excellence – Enabled by process maturity, tools and accelerators
Flexible engagement – Spans consulting, staffing, managed services, outsourcing, and cloud
Industry expertise – Driving depth in select industry verticals
Why NTT DATA for MS Services:
NTT DATA is a Microsoft Gold Certified Partner. We cover the entire MS Stack, from applications to infrastructure to the cloud
Proven track record with MS solutions delivered in the past 20 years

4. Drawing at the end of the session
Drop your business card or fill out provided blank card and drop in the red bag
Must be present at the time of drawing at the end of the session to win:

5. Agenda
Why & When?
What & How?
Q&A

6. Why do we need SLA’s
Management and coworkers need to understand and agree to reality
Help you to request and argue the resources you need
Avoid lawsuits

7. Rule Number One! SLA first Solution later
If you already have a solution don’t agree to a SLA the solution can’t support

8. What should be in a SLA? Everything Operational requirements
Maintenance windows
Responsibilities
Dependencies
What happens if the SLA is not met

9. RPO – Recovery Point Objective
In plain English: How much data can we lose?
Samples
Your last log backup is from 12 minutes ago 12 minutes
Your last full backup is from last week 1 week
You do not have a backup all

10. RTO – Recovery Time Objective
In plain English: How much time after a failure till we have to be available again
Samples
Your restore takes 6 hours 6+ hours
Your last backup does not work you have to go to tape hours

11. Availability
Time the database is available within a period of time divided by the length of the period of time.
Don’t confuse luck with availability!
How fast to you think you can fix data corruption or human error in your database?

12. Availability
99.0 %
99.7 %
99.9 %
99.99 %
% the famous five nines %

13. Availability how long can I be offline
1 Year
Days
Hours
Minutes
Seconds
1 Month 0%
365.25
8766
525960
730.5
43830
99.0 %
3.65
87.66
5260
315576
0.30
7.31
438
26298
99.7 %
1.10
26.30
1578
94673
2.19
131
7889
99.9 %
8.77
526
31558
0.73 44
2630
99.99 %
0.88 53
3156 4
263
99.999% 5
316 26 %
0.5 32 3

14. Available Is a database available when It is online in SSMS?
I can login?
I can select data?
I can update data?
I can insert data?
I can change the schema?
… you get the idea?
And don’t get me started on defining performance

15. When is a database needed?
Is the database used on the web 24x7 or just in the office from 9 to 5 or just once a month to process payroll?
Do the availability requirements apply all the time or just during the periods its actually used?

16. Service Windows Specify times when you can service your system
The more the better
Every night from 11pm till 5am, all day Saturday and Sunday, except the weekend before the year end results are due.
First Sunday every month from 2am till 4am

17. Planned versus Unplanned
Big debate is planned maintenance part of the yearly downtime or not?
Big difference between the two cases
Make sure its clearly defined and understood

18. Monitoring availability
99.999% is equivalent to less than 5.2 minutes of outage per year or less than a 0.8 seconds per day
This requires you to do an availability check at least every 0.4 seconds otherwise you waste valuable time.

19. Availability Having a certain availability vs. guaranteeing it.
Easy to end up with 100% availability
Hard to guarantee even 99.7

20. Differentiate between HA, DR and LR
HA … High Availability
DR … Disaster recovery
LR … Last Resort
Have different RPO and RTO values for all three cases.
Define worst case scenarios each level has to deal with

21. HA … High Availability RTO: seconds to minutes RPO: Zero to seconds
Automatic failover
HA site usually close by (< 30 miles)
Well tested (maybe with each patch or release)

22. DR … Disaster recovery RTO: minutes to hours
RPO: seconds to minutes (even hours)
Manual failover into prepared environment
DR site usually several hundred miles away
Tested from time to time

23. LR … Last Resort RTO: days to weeks
RPO: minutes to hours (even a whole day)
Rebuild system from scratch
Hardware has to be ordered
Floor space, connectivity to be rented
LR site usually on different continent and jurisdiction
Have a rough plan

24. Define worst case scenario for HA
Failure of a single component
Failure of two components (which are of a different kind)
Failure of server
Failure of multiple servers
Failure of any two components
That means you need everything at least three (3) times (not so easy for disks)

25. Define worst case scenario for DR
Human error
Failure of server
Failure of multiple servers
Partial failure of data center
Full failure of data center
Failure of multiple data centers

26. Define worst case scenario for LR
Destruction / failure of multiple datacenters
Natural disaster
Sabotage
Political incident (i.e. war, regime change)
Destruction of planet earth …

27. Outside SQL Server
Make sure you state that you depend on the underlying infrastructure and failures of that infrastructure don’t count for you!
Make sure no processes are interfering
Example: async database mirroring + failover OK for loosing data. Only one person allowed to give the OK. The guy is 3 weeks on vacation and availability is down to 94.2%

28. Dependencies Who needs this database/server
What does this server need to operate
Power
Cooling
Network
Firewall rules
Domain Controller
Other servers (linked server) …

29. Responsibilities
Who can actually make a decision for a database/server
Who owns the data
Who needs to be notified if something is wrong

30. Backup retention and granularity
How far must you be able to go back?
Hours, Days, Weeks, Months, Years
And how accurate must the restore be
I need the database restored to November 15, 2008 at 6:27…
How much time do you need for this historic restores
Test them from time to time (you need the resources and time)

31. Tips for keeping the SLA
Make sure your monitoring and alerting works
Monitor your Monitoring
Test your HA, DR, LR solutions regular and especially after every change to your infrastructure.

32. Surprise! Database Recovery It depends So somewhere between
On oldest uncommitted transaction
Number and size of transactions in flight that need rollback
So somewhere between
Less than a second
Several weeks
Surprise!

33. DR and LR Instructions
Keep printed copies in several places trust me your electronic documentation won’t be there when you are in a DR or LR situation

34. Summary Remember Rule Number one SLA first Solution later
If you already have a solution don’t agree to a SLA the solution can’t support
The laws of physics apply (even to the best DBA :-)

35. A good bare minimum SLA SLA HA DR LR Failure Modes (single failures)
RTO Seconds Minutes Hours Days
RPO Close to Zero Seconds to Minutes a lot
Failure Modes (single failures)
Single component failure  HA
Server failure  HA (DR)
Datacenter failure  DR
Network failure between datacenters  HA/DR
Data loss/corruption
Deletion  HA/DR/LR
Corruption  DR (LR)
Sabotage  LR (DR)
Concurrent failures
Any different double failure HA  DR
Any double failure DR  LR
Any triple failure LR
Priorities
Recoverability (no data loss)
Availability (keep going)
Performance (keep running)
Defined maintenance windows and adjusted values based on the day and time of the day

36. Sample SLA SLA HA DR LR During Maintenance Window
RTO < 30 Seconds < 30 Minutes 3 days
RPO Close to Zero up to 1 minute up to one day
During Maintenance Window
RTO N/A 30 Minutes after end of window 3 days
RPO N/A before maintenance window up to one day
Failure Modes (single failures)
Single component failure  HA
Server failure  HA
Datacenter failure  DR
Network failure between datacenters  DR
Data loss/corruption
Deletion  DR
Corruption  DR
Sabotage  LR
Concurrent failures
Any different double failure HA
Any double failure DR/LR
Any triple failure LR
Priorities
Recoverability (no data loss)
Availability (keep going)
Performance (keep running)
Defined maintenance windows Saturday 1pm till Sunday 9pm except if EOM

37. THANK YOU! and may the force be with you…
Questions?