One of the Best Oracle RAC Architecture Documents I’ve Ever Read
https://oracle-patches.com/en/databases/oracle/oracle-rac-networking-concepts-and-components
RAC
Basic ASM commands
Show ASM status srvctl status asm Show more detailed ASM configuration srvctl config asm sqlplus login to ASM sqlplus / as sysasm Show which ASM clients are connected to this ASM instance select instance_name, db_name, status from v $asm_client; The only parameter that must be set for an ASM instance is INSTANCE_TYPE=ASM. All others have …
Oracle RAC How to Configure High Availability NFS for Oracle Grid Infrastructure
Register a new HAVIP resource with “srvctl add havip” Create a shared Oracle ACFS file system – multi-step process on 12c, see Oracle Doc Here. Register a shared Oracle ACFS file system with “srvctl add filesystem”. Create the Oracle ACFS export resource with “srvctl add exportfs”. Note: the first two steps can be done in …
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Oracle RAC – What Are nodeapps ?
Nodeapps are a standard set of oracle application services which are started automatically for RAC. Node apps Include: 1) VIP. 2) Oracle Net listener. 3) Global Service Daemon. 4) Oracle Notification Service. Nodeapp Services run on each node of the cluster and will switched over to other nodes through VIP during the failover. #srvctl start …
Oracle RAC Tuning Sequences
Sequences in RAC environments encounter much less contention when a large cache is used and the sequence is defined as “noorder”. alter sequence seq1 cache 10000 noorder;
Oracle RAC 12.1.0.2 root script fails to start ora.ctssd if node name length are not the same
12.1.0.2 root script fails to start ora.ctssd if nodes name length are not the same (Doc ID 1918426.1) The bug is fixed in 12.1.0.2 GI PSU 1 and 12.2, the solution is to apply 12.1.0.2 GI PSU before executing root script (root.sh or rootupgrade.sh) I assume this is for all platforms – the doc id …
Oracle RAC – Query The GRD – and object locking
Oracle RAC stores a Global Resource Directory in the shared pool to help facilitate Cache Fusion. The following query displays much of it – and how much space is allocated. Note: I queried a very inactive sandbox of mine below. SELECT name, TRUNC( bytes/ 1024/ 1024, 2) size_MB FROM v$sgastat WHERE name LIKE ‘ges resource%’ …
Crucial Oracle RAC – Background Processes – Facilitate Cache Fusion
Background processes that support Oracle RAC Cache Fusion What is Cache Fusion? The general term used by Oracle to control the synchronization of SGA across database instances in a RAC cluster. The following background processes are used to implement it and are started on each instance when the instance starts. Generally, the processes below communicate …
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Oracle RAC – What causes a gcs log flush sync event?
Oracle RAC tracks wait time as a “gcs log flush sync” when a foreground process on one instance requests a block from another Oracle RAC instance that has uncommitted changes in the block requested – if those changes have not already been flushed to the local redo log. This will also occur if a block …
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Oracle RAC 11gR2 and 12c SCAN and Virtual IP and their purposes
Concerning Oracle RAC 12c, and 11gR2 Virtual IP (VIP) addresses are IP addresses pair with REAL IP addresses and are used to avoid TCP timeout which can be well into the minutes. Oracle RAC monitors VIP addresses for availability and moves them if necessary to available real IP addresses. VIP addresses are stored in DNS …
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