Cleaning up a failed Oracle 11g grid infrastructure install.

Unfortunately, the installer or more specifically the root.sh script for the Oracle 11g grid (Clusterware) installer can be very flaky.   If it fails and you need to fix something or rerun it for any reason, it will fail the next time if you have not cleaned up the install by de-configuring CRS. I also …

Read more

Using files on a shared drive as disks for ASM (on RedHat Linux)

Firstly, you need to create files padded to the required disk size. So if you want 4 1Gb files you could execute the below commands on shared storage: dd if=/dev/zero of=/SHAREDDISK/asmDisk1-1 bs=1024k count=1000 dd if=/dev/zero of=/SHAREDDISK/asmDisk1-2 bs=1024k count=1000 dd if=/dev/zero of=/SHAREDDISK/asmDisk1-3 bs=1024k count=1000 dd if=/dev/zero of=/SHAREDDISK/asmDisk1-4 bs=1024k count=1000 dd creates your file, ‘if’=/dev/zero gets null …

Read more

Error PRVF-5472 during an Oracle Grid infrastructure install

This is a problem with the config of the NTP daemon (ntpd) which synchronizes time across the cluster. The specific error is to do with the boot time behavior of the daemon and needing the ‘Slewing’ option enabled. If you need to enable slewing, you can do it by typing ‘ntpd -x’, however, the grid …

Read more

What is Hadoop?

If you have ever wondered what Hahoop, Memcached, NoSQL, Mapreduce or many of the other data based technologies that are springing up are, this is a superb whistle stop tour or the market.   Hadroop is basically a system for distributing your data across multiple storage servers that all have processing capacity. Then when you …

Read more

Oracle Direct NFS

Features embedded in Oracle Kernel Improves performance and manageability for NFS drives Configuring: NFS file system should be mounted and available. Direct NFS does not mount drives Direct NFS client uses either: configuration file called ‘oranfstab’ mount file tab – /etc/mtab First: $ ORACLE_HOME/ dbs/oranfstab which would specify the Direct NFS Client settings for a single database. Then /etc/oranfstab …

Read more

Oracle ASM

A brief discussion on Oracle ASM and some of its advantages over other file systems.     Notes: Database centric file system only used for managing database files High performance Requires a certain amount of tuning Not suitable for all applications Current recommendation is to allow ASM handle raid mirroring rather than let hardware handle it Probably …

Read more

Manually upgrading to 11g

You can directly upgrade an Oracle database from version 9.2.0.4 or higher, directly to 11g Upgrade Process. Open database in Upgrade mode:      startup upgrade Pre-Upgrade information tool:      utlu111i.sql Precursor to the upgrade. Generated report on required  and recommended changes to make.. Generally increasing tablespace sizes or remove parameters. Upgrade script:   …

Read more

Some notes on Oracle Indexes

Oracle Indexes The degree to which indexes help performance depends partly on the selectivity of the data.High selectivity – Few rows match the index valueLow selectivity – like Country name returns many rows from the index If data is selective but the rows are not stored near each other in the table, many blocks may …

Read more

How to remove old RMAN backup files.

It is possible to use operating system commands such as rm on linux to delete RMAN backup files and generally recover from it, however you are far better using built in RMAN commands to do this. $ rman target / NOCATALOG First, check that all backup files are still available. This will show whether files …

Read more