The extended or streched Oracle (RAC) cluster – part 1

for part 2, click here…

First of all, both terms ‘extended’ and ‘stretched’ are used on blogs, in documentation and logfiles. I will use ‘extended’ in this one. Also, voting files are files, not disks. Oracle will store the file(s) on one of the disks within the specified diskgroup, preferable in different failgroups. Also people talk about a ‘RAC’ cluster, but an Oracle cluster can exist without RAC. RAC is the database option to run the database in a cluster on Oracle clusterware.

Sorry, no images in this blog post… only text.

When is an Oracle cluster an extended/stretched cluster?

It’s not distance. Oracle does not know if it’s in the same or different racks or buildings, divided by roads or rivers…  There is no setting ‘extended=Y’ in Oracle that it knows about being extended.

It’s the way _you_ design the storage for Oracle clusterware and ASM.

My point of view, extended is; When there is mirroring of blocks on disks and these mirrored blocks are on disks in different storage locations. Continue reading

Oracle Database 11g Release 2 Launch

After a nice Lower Cost talk by Mark Townsend and the new Sun Oracle Exadata and Database Machine by Chris Baker, I attended ‘Upgrade to 11g – Best Practices’ by Mike Dietrich, ‘Consolidate on Low-Cost Server and Storage Grids’ by John Abrahams, ‘Oracle’s Maximum Availability Architecture’ also by John Abrahams & Lucas Jellema, CTO AMIS and ‘DBA 2.0’ by Ed Bangma.

It was nice to see our Whitehorses logo in the main presentation at the Oracle Netherlands 25 years sheet!

More on Oracle ASM Cluster File Management, Dynamic Volume Manager, RAC One Node, Grid Plug ‘n Play, Server Pools, Cluster Health Monitor and Electronic Sudoku Devices… Continue reading

DB instances does not wait for ASM to be finished

Yesterday, I came across a small problem with an Oracle RAC installation using ASM. After a restart of one of the three (Windows Server 2003) nodes, three of the five database instances did not start automatically…

Running ‘crs_stat’ showed status OFFLINE and target ONLINE for these instances, but strangely there was no entry in the alert log telling these instances did not start because of ’something’ was wrong. It even looked like that they did not got any signal to start at all! OK, so I checked the CRS log for any strange behavior and it showed ASM finishing after the database instances gave up starting.

A quick search on the ‘new and improved’ My Oracle Support (old Metalink), resulted in running ‘crs_stat -p’ and check for [REQUIRED_RESOURCES=] for each instance. It showed that for the particular node, ASM was not required for these three database instances. Modifying this with ’srvctl modify instance -d db1 -i node1 -s +ASM1′ (for example), did the trick.

I found this solution on Metalink: Doc ID: NOTE:276208.1 “CRS is not starting first the ASM instance”, although I can not imagine hitting this bug on

Happy consulting!