OCS Examiner - Amazon S3 · 2018-02-18 · Oracle 12.1 Enterprise Edition Active Data Guard with...

© All Rights Reserved. Axxana 2015

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© All Rights Reserved. Axxana 2007-2018 RMOUG Training Days 2018 #TD18 #TD2018Squeezing the Max out of 12c Disaster Recovery

Squeezing the Max out of 12c Disaster Recovery

Yossi Nixon, Chief Database ArchitectFebruary 2018


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© All Rights Reserved. Axxana 2007-2018 RMOUG Training Days 2018 #TD18 #TD2018Squeezing the Max out of 12c Disaster Recovery© All Rights Reserved. Axxana 2007-2018 RMOUG Training Days 2018 #TD18 #TD2018Squeezing the Max out of 12c Disaster Recovery

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Speaker

Yossi Nixon

Chief Database Architect

Oracle DBA since 1998

Specializes in Data Guard, RAC, performance tuning.

@YossiNixon

www.linkedin.com/in/ynixon

oracledba.blogspot.com


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Data Guard Overview

Enhancements in Oracle 12c and 18c

Benchmark and Lessons Learned

The Risk-Distance Conundrum

Axxana’s Phoenix Technology

Putting it all together

Agenda

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Title


Data Guard Overview

Primary RemoteStandby

ASYNC


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Title


6

Data Guard Terms

Redo Compression

11g

SYSDG Role

12cFlashback Database on Data Guard

10g

Fast Start Failover

FSFO10g

Online Standby

Database File Rename

12c

Switchover / Failover

Snapshot Standby

11g

Cascaded Redo

9iRMANDuplicate

from Active Database

11g

Automatic Gap

Resolution9iActive

Data Guard

11g

Read-Only Physical Standby

8i

Far Sync12c

Standby Redo Logs

10g

Real-time apply

10g

Managed Recovery

8i

Fast Sync12c

Data Guard Broker


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Active Data Guard Far Sync

Far Sync

Primary RemoteStandby

ASYNC - Alternate

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Title


Redo

Far Sync

ASYNC

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Very promising for long distance replication if data loss is not acceptable

Up to 60% performance gain (DML only workloads) with 25ms network latency

Lightweight and easy to deploy (virtual machine)

If latency <5ms most likely you don’t need Far Sync

Far Sync Summary

25ms

SYNCPrimary Standby


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Far Sync Syntax

SQL > ALTER DATABASE CREATE FAR SYNC INSTANCE

CONTROLFILE AS ‘/tmp/farsync.ctl’;

SQL > create pfile=‘/tmp/initfs.ora' from spfile;

SQL > ALTER DATABASE ADD STANDBY LOGFILE THREAD 2

SIZE 52428800;

SQL > create spfile from pfile=‘/tmp/initfs.ora';

DGMGRL> ADD FAR_SYNC fs AS CONNECT IDENTIFIER IS fs;

DGMGRL> EDIT DATABASE pdb SET PROPERTY RedoRoutes = '(LOCAL

: fs SYNC ALT =(sdb ASYNC FALLBACK))';

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https://oracledba.blogspot.com/2017/08/creating-far-sync-instance-step-by-step.html

https://oracledba.blogspot.com/2017/08/creating-far-sync-instance-step-by-step.html


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Lab Environment Setup

Oracle 12.1 Enterprise EditionActive Data Guard with Far Sync, ASM, Requested tailored patches for Far Sync, Oracle Linux 7.2

Server environmentPrimary & Standby – 2 x Lenovo X3550 M5 (2 x Xeon E5-2620 V3 2.4Ghz, 32GB memory, 4 SSDs)

Far Sync – Two configurations

i7/16GB/dual SSD

Quad Xeon/32GB/4 SSDs

Neutralized network latency issues10GbE connectivity, All systems are collocated

1 to 16 instancesUp to 8 instances on each primary/secondary server, Up to 16 instances on Far Sync server

Primary

Standby

Far SyncHub

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Standby


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Setup Observations

Local Far Sync

Primary StandbyRemote Far Sync

ASYNC - AlternateAlternate

opposite direction

Maximum Availability

no multiplex

RMAN deletion policy


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✅Memory Consumption

✅ Networking

✅ Latency reduction through Fast Sync

✅ CPU Consumption

✅ Far Sync IO patterns

Lessons Learned


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Configuration

Used the recommended SGA allocation (300MB SGA)

The Far Sync instance requires a very small SGA footprint (much less than production)

No database files

No media recovery

Consider allocating memory for storage cache

Memory Consumption


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Configuration

Jumbo frames make a huge difference (MTU 9000)

Bonding two 10GbE ports

Network Traffic is Consistent with Log File Write throughput

Bytes written = Bytes received by Far Sync Instance = Bytes Sent by Far Sync Instance

To maximize throughput tune: MAX_CONNECTIONS, LOG_ARCHIVE_MAX_PROCESSES and TCP Send/Receive Buffer Sizes

Transport compression will reduce traffic… but takes its toll on CPU cycles…

Networking


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Standby acknowledges the primary as soon as it receives redo in memory, Without waiting for disk I/O to a standby redo log file

Main goal is shortening the total round-trip time between primary and standby

We didn’t see significant benefit from Fast Sync (NOAFFIRM), since our SSDs are already fast enough.

Latency Reduction – Fast Sync


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Followed Oracle’s recommendationReducing the CPU_COUNT during testing had no effect on the

performance of the Far sync instance

Virtual Keeper of Time Process(es) (VKTM) are high CPU consumer

One process per Database and ASM instances

Several “solutions” have been recommended to reduce its priority

✅ Significant improvement achieved when Far Sync runs multiple instances!

Transport compression takes its toll on CPU cycles…

CPU Consumption


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Redo entries stored in Standby Redo Logs and Archives

Far Sync doesn’t take advantage of log_buffer memory to reduce I/O

IOs may be reduced through smart caching techniques…

Reduce Redo Log members

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Far Sync IO Patterns

StandbyRedoLogs

Archives

1 2

3 4

Cache

Far Sync

RemoteStandbyPrimary

Rea

d

Wri

te


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Without cache, reads and writes follow a very regular and similar pattern (2 writes and 2 reads for each entry received). Write throughput peaks at < 1000MB/sec

Far Sync IO Patterns – No Cache


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With “write through” cache, all reads can be satisfied from the cache. Write throughput peaks at 1200MB/sec (20% improvement vs no cache)

Far Sync IO Patterns – Writethrough


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During “normal operation”, Far Sync reads the Standby Redo Log twice

1. To send the data to the remote Standby

2. To create the archived redo log

Archives are only written

Recommendation – Create two volumes1. For Standby Redo Log, use “Writethrough” caching

2. For archives, use “No Cache”

During backlog, the cache saves only “one” readArchive creation reads from cache

But data sent to the remote standby is read from the archives

To Cache or not to Cache?


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Assumption:

As a rule, backlog can be satisfied from standby redo logs

Cache should be large enough to hold all standby redo logs:

E.g., 10 groups, each of 4GB => 40GB cache

How much cache?


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Archiving process stresses the IO subsystem

When dealing with multiple instances, try to avoid concurrent archival processes, to achieve smoother IO patterns

Archiving process “interference”

Redo I/O

Redo I/O


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Using Data Guard Broker is strongly recommended, especially when using Far Sync

No “easy” way to collect database statistics, since Far Sync is not a database!

When using Far Sync, use the latest patchsets

Rolling Forward a Physical Standby Database Using the RECOVER FROM SERVICE is cool (First introduced in Oracle 12.1)

Additional Observations (cont.)


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Multi-Instance Redo Apply

Data Guard Creation with dbca

Fast Failover - Data Guard take over session draining

Password file is managed and transported via the Redo mechanism

Supports AWR on Active DG for the standby

Multiple Observers

Alternate prioritization

Block Comparison tool in DGMGRL

Oracle 12.2 Main New Features

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In Memory Column store works with multi-instance redo apply

Multi-instance redo apply support with Block Change Tracking (BCT).

Global Temporary Table support from Standby.

DML operations on Standby – Redirection to Primary without ACID compromise.

Preserve buffer cache during role-change.

No logging enhancement - Performance mode and Availability mode.

Oracle 18c New Features

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Distance Between Primary and Far Sync

Distance-Risk Conundrum


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Axxana – Transparent Layered Protection

Physical Protection

Multiple Network Connectivity

WAN, LAN, Wi-Fi, 4G

Battery Powered

Data Safe

PhoenixOSSmart DR

Far SyncVirtual

Machine

Managedby theUser

Transparently Managed

byAxxana


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Active Data Guard Far Sync with Axxana

Primary Remote Standby

ASYNC over 10GbE

Zero Distance

SYNCRecovery over

Cellular/1GbE/10GbE

Axxana ProtectedFar Sync


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Short Video

Video Source: http://www.axxana.com/wp-content/uploads/2016/07/x.mp4


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Winning Combination

AxxanaBlack Box

PhoenixOS

OracleActive Data

GuardFar Sync

✅ Zero Data Loss at any distance

✅ No latency (round-trip time) Compromise

✅ True Protection against Link Failure

✅ Application Consistency Guarantee


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See for yourself…

Video Source: https://youtu.be/ROqI5oR6g8s


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Yossi NixonTwitter: @YossiNixonLinkedin: https://www.linkedin.com/in/ynixon/Blog: https://oracledba.blogspot.comEmail: [email protected] / [email protected]: Oracle DBA's in Israel

https://twitter.com/yossinixon

https://www.linkedin.com/in/ynixon/

https://oracledba.blogspot.com/

mailto:[email protected]

mailto:[email protected]

https://www.facebook.com/groups/orcldba

OCS Examiner - Amazon S3 · 2018-02-18 · Oracle 12.1 Enterprise Edition Active Data Guard with...

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