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©2017 ScaleArc. All Rights Reserved. 1 Achieving Zero Downtime for SQL
20

Achieving Zero Downtime for SQL

Apr 14, 2017

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Page 1: Achieving Zero Downtime for SQL

Achieving Zero Downtime for SQL

Page 2: Achieving Zero Downtime for SQL

©2017 ScaleArc. All Rights Reserved. 2

Downtime is disruptive and costly

• Poor user experience• Decreased productivity• Wasted time and IT resources• Lost revenue

Page 3: Achieving Zero Downtime for SQL

©2017 ScaleArc. All Rights Reserved. 3

Two Sources of Downtime

• Unplanned Outages– A strong failover architecture is imperative

– Instantly identify and automatically reroute traffic away from a failed database server, even across data centers

– Avoid application errors and user dissatisfaction

• Planned Maintenance– Carefully examine your database maintenance strategy

• Are you bringing servers completely offline for maintenance?

• Are you disabling applications associated with those databases during maintenance?

Page 4: Achieving Zero Downtime for SQL

©2017 ScaleArc. All Rights Reserved. 4

Want Guaranteed Downtime?

Keep your applications directly connected to your databases

This 1:1 tie will guarantee that any database hiccup will make your application

throw up

Or…

Page 5: Achieving Zero Downtime for SQL

©2017 ScaleArc. All Rights Reserved. 5

Leverage the Fact that Databases are Getting Smarter

Modern databases offer:• Scale out• Better replication• Automatic failover

But make one key change:End the 1:1 tie between apps and databases by inserting an

abstraction layer.

Page 6: Achieving Zero Downtime for SQL

©2017 ScaleArc. All Rights Reserved. 6

An Abstraction Layer is Critical for Zero Downtime

• Database Load Balancing Software acts as a buffer

PrimaryPrimary SecondaryPrimary

replicationSecondary

• Leverages database replication and failover

• Makes failover invisible to the app by queing writes until the new primary is ready

• Enables servers to go offline for maintenance without taking down the app

Database Load Balancing Software

Page 7: Achieving Zero Downtime for SQL

©2017 ScaleArc. All Rights Reserved. 7

ScaleArc’s Database Load Balancing Software

• Intelligently directs traffic into the database on behalf of the app• Deploys transparently, with no changes to app or database• Leverages and augments database’s replication and failover

Page 8: Achieving Zero Downtime for SQL

©2017 ScaleArc. All Rights Reserved. 8

Avoid Downtime during Unplanned Outages

PrimaryPrimary SecondaryPrimary

replicationSecondary

Page 9: Achieving Zero Downtime for SQL

©2017 ScaleArc. All Rights Reserved. 9

PrimaryPrimary SecondaryPrimary

replication

Avoid Downtime during Unplanned Outages

Secondary

1 ScaleArc performs read/write split

Page 10: Achieving Zero Downtime for SQL

©2017 ScaleArc. All Rights Reserved. 10

PrimaryPrimary SecondaryPrimary

replication

Avoid Downtime during Unplanned Outages

Secondary

1 ScaleArc performs read/write split

RRR

WR W R R

W

Page 11: Achieving Zero Downtime for SQL

©2017 ScaleArc. All Rights Reserved. 11

Primary Secondary

replication

Avoid Downtime during Unplanned Outages

Secondary

1 ScaleArc performs read/write split

R

WR W R R

W2 Upon database failure,

ScaleArc queues writesW

W

Page 12: Achieving Zero Downtime for SQL

©2017 ScaleArc. All Rights Reserved. 12

Primary Secondary

replication

Avoid Downtime during Unplanned Outages

Secondary

1 ScaleArc performs read/write split

R

WR W R R

2 Upon database failure, ScaleArc queues writes

3 After secondary is promoted, ScaleArc directs queries to new primary server

Primary

WWW

Page 13: Achieving Zero Downtime for SQL

©2017 ScaleArc. All Rights Reserved. 13

Primary Secondary

replication

Avoid Downtime during Unplanned Outages

Secondary

1 ScaleArc performs read/write split

R

WR W R R

2 Upon database failure, ScaleArc queues writes

3 After secondary is promoted, ScaleArc directs queries to new primary server

Primary

WWW

4 Apps see delay, but do not restart

Page 14: Achieving Zero Downtime for SQL

©2017 ScaleArc. All Rights Reserved. 14

SecondarySecondary

replication

Enable Zero Downtime Maintenance

SecondaryPrimary

WRRWR

RW

WR R

Page 15: Achieving Zero Downtime for SQL

©2017 ScaleArc. All Rights Reserved. 15

Secondary

replication

Enable Zero Downtime Maintenance

Secondary

1 Mark a database to be taken offline

Primary

WRRWR

RW

WR R

Page 16: Achieving Zero Downtime for SQL

©2017 ScaleArc. All Rights Reserved. 16

Secondary

replication

Enable Zero Downtime Maintenance

Secondary

1 Mark a database to be taken offline

Primary

WRRWR

RW

WR

2 ScaleArc automatically reroutes queries away from offline server

Page 17: Achieving Zero Downtime for SQL

©2017 ScaleArc. All Rights Reserved. 17

Secondary

replication

Enable Zero Downtime Maintenance

Secondary

1 Mark a database to be taken offline

Primary

WRRWR

RW

WR

2 ScaleArc automatically reroutes queries away from offline server

3 Patch the server and bring it back online

Page 18: Achieving Zero Downtime for SQL

©2017 ScaleArc. All Rights Reserved. 18

SecondarySecondary

replication

Enable Zero Downtime Maintenance

SecondaryPrimary

WRRWR

RW

WR R

4 After health check, ScaleArc auto restores traffic to updated server

3 Patch the server and bring it back online

2 ScaleArc automatically reroutes queries away from offline server

1 Mark a database to be taken offline

Page 19: Achieving Zero Downtime for SQL

©2017 ScaleArc. All Rights Reserved. 19

ScaleArc Keeps Business Data Flowing

• Avoid lost productivity and business profitability• Ensure customer satisfaction• Keep critical data flowing

Page 20: Achieving Zero Downtime for SQL

©2017 ScaleArc. All Rights Reserved. 20

Achieving Zero Downtime for SQL

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