Sybase Replication Server - Warm Standby Setup

Sybase Replication Server

Step-by-step instructions to install a warm standby Replication Server

Create a maintenance user on the Primary and Replicate Sybase ASE dataservers.

The maintenance user, typically <db>_maint, is used to server to apply replicated transactions at the destination dataserver. Under normal circumstances you would not change the name and password of the maintenance user. Ensure that these values are identical at the source and destination. Also since the databases will be synced using a database backup and restore, it will help to sync logins on the primary and replicate dataservers. This can be achieved by Bcp-ing syslogins and sysloginroles.

The following acronyms are used for various entities in the replication topology

PDB – Primary database

RDB – Replicate database

RS - Replication server

PDS – Primary Dataserver

RDS – Replicate Dataserver

It is assumed that databases <PDS>.<PDB>and <RDS>.<RDB> exist and are the same size.

STEP 1 : Create logins on PDS and RDS

isql –Usa –P<sa_password> -S<PDS>

sp_addlogin "<rep_maint_user>","<rep_maint_pswd>"gogrant role replication_role to "<rep_maint_user>"go-- check the value of the suidselect suser_id("<rep_maint_user>")go

use <PDB>gosp_addalias "<rep_maint_user>","dbo"go

isql –Usa –P<sa_password> -S<RDS>

sp_addlogin "<rep_maint_user>","<rep_maint_pswd>"gogrant role replication_role to "<rep_maint_user>"go-- check the value of the suidselect suser_id("<rep_maint_user>")gouse <RDB>gosp_addalias "<rep_maint_user>","dbo"go

STEP 2 : Install the replication server stored procedures and tables

Execute the script rs_install_primary.sql located in $SYBASE/$SYBASE_REP/script in both the PDB and RDB databases. Please comment out commands “dbcc settrunc” and “sp_setreplicate” in the script since these need to be run after the replication agent is configured.

isql -Usa -P<sa_password> -S<PDS> –D<PDB> -i rs_install_primary.sql isql -Usa -P<sa_password> -S<RDS> –D<RDB> -i rs_install_primary.sql

STEP 3 : Configure ASE dataservers for replication

This step is essentially to enable rep agent threads

isql -Usa -P<sa_password> -S<PDS>

sp_configure "enable rep agent threads",1 go

isql -Usa -P<sa_password> -S<RDS> sp_configure "enable rep agent threads",1go

STEP 4 : Create logical connection on the replication server

Name of the logical connection below is <PDS>.<PDB> and but refers to the current primary data source

isql -Usa -P<sa_password> -S<RDS>_rs

create logical connection to <PDS>.<PDB>go

STEP 5 : Create connection to the active database

isql -Usa -P<sa_password> -S<RS>

create connection to <PDS>.<PDB>set error class to rs_sqlserver_error_classset function string class to rs_sqlserver_function_classset username to <rep_maint_user>set password to <rep_maint_pswd>with log transfer onas active for <PDS>.<PDB>go

STEP 6 : Create the maintenance login on the replication server

This login is used by the replication agent running in the ASE to connect to the replication server.


create user <rep_maint_user> set password <rep_maint_passwd>gogrant connect source to <rep_maint_user>go

STEP 7 : Configure replication agent


use <PDB>go-- This will clear previously installed rep agents. Ho harm if none are present.sp_config_rep_agent "<PDB>", "disable"go-- Continue installing rep agent.sp_config_rep_agent "<PDB>", "enable", "<RDS>_rs", "<rep_maint_user>", "<rep_maint_pswd>"gosp_config_rep_agent "<PDB>", "send warm standby xacts", truego

sp_setreplicate rs_marker,"true"gosp_setreplicate rs_update_lastcommit,"true"gosp_start_rep_agent "<PDB>"go

STEP 8 : Mark the database for replication

Execute the sp_reptostandby stored procedure in the primary or active ASE to activate replication from the active database to the replication server.


use <PDB>gosp_reptostandby "<PDB>","all"go

STEP 9 : Create connection to the standby database


create connection to <RDS>.<RDB>set error class to rs_sqlserver_error_classset function string class to rs_sqlserver_function_classset username to <rep_maint_user>set password to <rep_maint_pswd>with log transfer onas standby for <PDS>.<PDB>use dump marker go

STEP 10 : Check the status of replication connections


admin logical_statusgo

This command should show the primary and standby connections active and the standby connection awaiting “enable marker”


admin who_is_downgo

DSI threads to <RDS>.<RDB> should be DOWN.

STEP 11 : Dump the primary database


dump database <PDB> to "<dump_device>"go

STEP 12 : Restore standby database from the dump

isql -Usa -P<sa_password> -S<RDS>

load database <RDB> from "<dump_device>"goonline database <RDB>go

STEP 13 : Resume connection to the standby database


resume connection to <RDS>.<RDB>go

STEP 14 : Test replication

Test Replication Connection


use <PDB>go--create a test tablecreate table dummy (f1 int)goinsert dummy select 1go


use <RDB>goselect * from dummygo

f1-----1

Sybase Replication Server Maintenance

Health Checks

The following commands are being used to check the replication system.

isql -Usa -P<sa_password> -S<RS>>admin who_is_down>go.

isql -Usa -P<sa_password> -S<RS>>admin health>go

isql -Usa -P<sa_password> -S<RS>>admin logical_status>go

Re-Syncing the Standby Database

Sometimes it may be necessary to resync the warm standby database. This could be due to replication errors, huge data updates in case of which it is preferred to break replication and restart it after the update or due to replication changes to text or image columns.

In such case the steps to resync a warmstandby database are as follows:

Suspend connection to <RDB> Drop connection to <RDB> Stop the replication agent on <PDB> Create connection to <RDB> with dump marker Start replication agent on <PDB> Dump the primary database Load database dump to the standby database Resume connection to <RDB>

These are the commands used to re-sync a standby database.


>suspend connection to <RDS>.<RDB>>go>drop connection to <RDS>.<RDB>>go

isql -Usa -P<sa_password> -S<priamary_server>

>use <PDB>>go>sp_stop_rep_agent "<PDB>">go


>create connection to <RDS>.<RDB>>set error class to rs_sqlserver_error_class>set function string class to rs_sqlserver_function_class>set username to <PDB>_repset password to <password>>with log transfer on>as standby for <PDS>.<PDB>>use dump marker >go


>use <PDB>>go>sp_start_rep_agent "<PDB">go


>admin logical_status>go

--this should display Suspended/Awaiting for Enable Marker on <RDS>.<RDB>. DO NOT PROCEED unless this any issues are fixed


>dump database <PDB> to "<file-name>">go

isql -Usa -P<sa_password> -S<RDS>

>load database <RDB> from "<file-name>">go>online database <RDB>>go


>resume connection to <RDS>.<RDB>>go

~ good luck ~

Documents

Sybase Replication Server - Warm Standby Setup