Feroz DBA'S Blog

---- RMAN ---- backup strategy --------------- We are using tape backup every Sunday - Level 0 backup (full) from Monday to sat - incremental backup every 1 hour - archive log backup Hot vs cold backup ------------------- what is difference --> what is the benefit cold backup does not required recovery - because it is a consistent backup hot backup needs recovery -- because during backup time data will modify restore vs recovery -------------------- restore - restoring datafile from secondary backup location to primary location like from tape to disk recovery- applying archivelogs - doing this it make database into consistent state scenario -------- 1. If datafile SCN is higher than the other datafiles - what is the reason and how you do recovery 2. If i have 2 system datafiles, one of the datafile is lost (someone removed from OS level) can you bring the database in mount state? 1. How to check backups are failed? - V$RMAN_BACKUP_JOB_DETAILS 2. How to resolve backu...

How to connect to mongodb server (specific to the replication enabled database)   mongo "mongodb://localhost:27018,localhost:27019,localhost:27020/myDB?replicaSet=rs0" Replica Status rs.status() Example MongoDB rs0:PRIMARY> rs.status() {         "set" : "rs0",         "date" : ISODate("2020-07-09T11:57:31.329Z"),         "myState" : 1,         "term" : NumberLong(1),         "syncingTo" : "",         "syncSourceHost" : "",         "syncSourceId" : -1,         "heartbeatIntervalMillis" : NumberLong(2000),         "majorityVoteCount" : 2,         "writeMajorityCount" : 2,         "optimes" : {                 "lastCommittedOpTime" : {                 ...

What is snapshot standby and its Benefits? A snapshot standby database is a fully updatable standby database that is created by converting a physical standby database into a snapshot standby database. A snapshot standby database receives and archives, but does not apply, redo data from a primary database. Redo data received from the primary database is applied when a snapshot standby database is converted back into a physical standby database, after discarding all local updates to the snapshot standby database. A snapshot standby database typically diverges from its primary database over time because redo data from the primary database is not applied as it is received. Local updates to the snapshot standby database will cause additional divergence. The data in the primary database is fully protected, however, because a snapshot standby can be converted back into a physical standby database at any time, and the redo data received from the primary will then be applied. A snapshot s...

1.        Environment details Environments Primary server DR server Database SID PRIM12 PRIM12 DB Unique name PRIM12 STND12 Database role Primary Standby (READ-ONLY) Database version 12.2.0.1 (64 bits) 12.2.0.1 (64 bits) Operating system RHEL 6.9 RHEL 6.9 ORACLE_HOME /u01/app/oracle/product/12.2.0.1/db_1 /u01/app/oracle/product/12.2.0.1/db_1   2.       Database Roles details 2.1. Primary database - PRIM12 SYS@PRIM121 > SELECT NAME, DB_UNIQUE_NAME, OPEN_MODE, DATABASE_ROLE FROM V$DATABASE; NAME       DB_UNIQUE_NAME                  OPEN_MODE             DATABASE_ROLE --------- ------------------------------ ----...