Do I still need to have SG, if I have oracle RAC and CRS&CSS?

[Hanry Zhou]

and why?


Thanks,
Roger

[Duncan Edmonstone]

If you're referring to 9i RAC then you*must* use Serviceguard.

If you're referring to 10g or 11g, then no you don't *have* to use Serviceguard, but there are plenty of good reasons to consider it anyway.

See my post in this thread which was asking roughly the same thing:

http://forums11.itrc.hp.com/service/forums/questionanswer.do?threadId=1227660

HTH

Duncan

[Steven E. Protter]

Shalom Roger,

As noted above RAC 9 won't work without SG, and 10/11 RAC allow you to not use SG.

SG license is expensive, and running two clustering environments on the same High Availability system is difficult and can lead to unexpected results.

There are good reasons to do this, such as needing to have a High Availability NFS share, but when possible, eliminate do not add complexity.

SEP

[Duncan Edmonstone]

I'm going to disagree with SEP on this one. When SG and CRS/CSS are both installed on the same system, you don't have 2 clustering solutions - you have one - Serviceguard is in control and CRS/CSS uses Serviceguard to get all ist cluster membership etc.

There are plenty more reasons that just HA NFS to use SG with RAC on 10g/11g - some of which I describe in my post on the link above. Using SG and CRS/CSS together needn't be over-complex and brings real benefits.

HTH

Duncan

[Hanry Zhou]

I am asking if SG should be used with RAC10g R2, and why?

My impression is RAC10g R2 can provide failed-over functions, but withough SG, the degree HA maybe not 100% covered comparing to (SG&RAC10g R2). If that is true, in what circumstances, RAC10g R2 may not able to prevent single point failure.

[Thomas J. Harrold]

Roger,

If you have another application that will need to be clusted on the same nodes, you'll need ServiceGuard.

CRS/RAC will not allow you to cluster non-oracle apps at this point. (despite the fact that CRS is just TruCluster)

I absolutely despise CRS - it's buggy, and convoluted. But it can work consistently if properly configured. I highly recommend the serviceguard toolkit for RAC.


-tjh