diffrence of rac cluster and extended rac cluster?

[prasanth.ps]

Hi All.,

Please tell me the exact difference between the implementation in oracle rac and extended oracle rac?

iS IT any diffrence between in HP UX side to implement the both?

[Matti_Kurkela]

Disclaimer: I don't have any experience on extended RAC (more properly, "Oracle RAC Extended Distance Cluster"). I just took a quick look through the documentation.

It seems to me that the difference in principle between Standard RAC and Extended RAC is similar to the difference between basic ServiceGuard and MetroCluster: instead of one shared storage device, you'll have two storage systems mirroring the data between them.

Oracle seems to allow various ways to configure the storage for Extended RAC. The requirements for configuration at the HP-UX level will depend on which method is chosen.

One thing I can say for sure, though: in an Extended RAC system, you will have a lot more disk device files (/dev/dsk/* or /dev/disk/*) than in an equivalent Standard RAC system. You will have to keep track which of these devices are local and which belong to the remote site. You must know (and document) how the disks of Site A are mirrored to Site B. There will be a lot of important details which are not needed on a Standard RAC.

MK

[prasanth.ps]

Hi,

Can you please forward me some docs regarding this?

It will be helpful for me to understand more on that.

Thanx and rgds,

Prasanth.

[Matti_Kurkela]

Why, Oracle has plenty of documentation available:

http://www.oracle.com/technology/products/database/clustering/index.html

I'd recommend starting with this one:
http://www.oracle.com/technology/products/database/clustering/pdf/ExtendedRAC10gR2.pdf

Although it is about an older version of Oracle Database, it seems to explain the fundamental idea of the Extended Distance RAC pretty well.

MK