OracleData Guard

Standby redo log configuration

Standby redo logs by thread. You want one more group per thread than you have online log groups, all the same size as the online logs.

Not yet verified. How scripts are tested

1CLEAR COLUMNS2SET LINESIZE 100 PAGESIZE 100 TRIMOUT ON TAB OFF3COLUMN group#   HEADING "GROUP"   FORMAT 9994COLUMN thread#  HEADING "THREAD"  FORMAT 9995COLUMN size_mb  HEADING "SIZE MB" FORMAT 99,9906COLUMN status   FORMAT A127 8SELECT group#, thread#, ROUND(bytes / 1048576) AS size_mb, status9FROM v$standby_log10ORDER BY thread#, group#;

Save it as ora-dg-srl.sql and run it with SQL> @ora-dg-srl.

Open in denrepoRelated tool: Redo log sizing

Part of these runbooks

• Data Guard check

More Oracle scripts: Data Guard

• Transport and apply lagHow far behind the standby is in receiving and applying redo. A growing apply lag with no transport lag points at the apply process, not the network.
• Redo apply and transport processesWhich Data Guard processes are running and what they're doing. No MRP0 row means redo is arriving but not being applied. Before 12.2, query…
• Redo destinations and transport errorsEvery active archive destination with its status, gap state and last error. Any text in the ERROR column means redo isn't reaching that standby.
• Archive gaps and last applied sequenceMissing log sequences the standby is waiting for, then the last applied sequence per thread. Compare with the current sequence on the primary.
• Data Guard errors and warnings, last 24 hoursMessages Data Guard wrote to V$DATAGUARD_STATUS, filtered to warnings and errors. Run on both sides.
• Broker health checks (DGMGRL)The broker's own view of the configuration. VALIDATE DATABASE is the best single readiness check before a switchover.