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Service Guard with RAC

Syed Muqtader Ali
Occasional Visitor

Service Guard with RAC

Dear Experts ,

Since long time iam getting confused on one issue and the issue is

basically their is oracle 10gRAC installed on 2 hp nodes and its connected to san for shared memory disk here they installed the service guard too
Please my question is any one can give me clear picture why they need to installed service guard on over setup

awaiting replie


12 REPLIES
Court Campbell
Honored Contributor

Re: Service Guard with RAC

To keep it simple -- you need to have serviceguard installed in order to run rac on hp-ux. unfortunately it is not like a rac install on Linux where you don't need a third party clustering software.
"The difference between me and you? I will read the man page." and "Respect the hat." and "You could just do a search on ITRC, you don't need to start a thread on a topic that's been answered 100 times already." Oh, and "What. no points???"
Steven E. Protter
Exalted Contributor

Re: Service Guard with RAC

Shalom,

With RAC version 9 on HP-UX serviceguard was a requirement prior to installation.

For 10gRAC, it is not a requirement but it may be depending on how you intend to use 10gRAC.

To maintain shared storage under certain circumstances you may still need serviceguard.

Whether or nor you need it is dependent on how you intend to use RAC and what options are needed. I just had a conversation on this with a DBA 30 seconds ago and he assures me that Serviceguard may not be required for 10gRAC, which has its own built in clustering software.

SEP
Steven E Protter
Owner of ISN Corporation
http://isnamerica.com
http://hpuxconsulting.com
Sponsor: http://hpux.ws
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Founder http://newdatacloud.com
Syed Muqtader Ali
Occasional Visitor

Re: Service Guard with RAC

Thanks for sharing knowledge friends..

In 10grac , basically it used Clusterware software (OCR+ voting disk) for oracle clustering.. so then what is the requirment of service guard

Court Campbell, you mean to say that Service guard is used to do operating system kind of Clustering

Sep, To maintain shared storage under certain circumstances you may still need serviceguard.

please can you describe the circumstances under shared memory storage for SAN

Cheers
Syed
Steven E. Protter
Exalted Contributor

Re: Service Guard with RAC

Shalom again,

One thing I saw that makes no sense was that one shop running oracle RAC wrote all logs to an NFS share that was controlled by the "active" node.

This was to permit the second node to write to the shame NFS share.

Few problems: NFS log writes going through the network, which was 100 BaseT are substantially slower than writing directly to shared storage, which was accessible to both RAC nodes.

But the site refused to drop NFS, so serviceguard had to be installed to make sure the NFS share stayed with the active node.

I do not believe you NEED serviceguard with 10G unless your configuration has requirements to manage some resource that the Oracle clusterware software can not manage. Such as a NFS share.

SEP
Steven E Protter
Owner of ISN Corporation
http://isnamerica.com
http://hpuxconsulting.com
Sponsor: http://hpux.ws
Twitter: http://twitter.com/hpuxlinux
Founder http://newdatacloud.com
Duncan Edmonstone
Honored Contributor

Re: Service Guard with RAC

Why would you use the Serviceguard clusterware if implementing RAC on HP-UX?

There are a few reasons I can think of:

i) Network protection - Serviceguard provides protection from network failure, CRS doesn't.

ii) Interconnect monitoring - Serviceguard can monitor and take action on the cache fusion interconnect more effecitively than CRS.

iii) Kernel integration - CRS is an all user space process, whereas Serviceguard is able to take advantage of the kernel safety timer - this provides much better hung node detection on HP-UX. Note on Linux Oracle can and do have a kernel module that provides a similar function.

iv) Cluster Filesystem - some people can't or don't want to use raw disks or ASM - With Serviceguard you also have the option of using a cluster filesystem.

v) Integration with HP's other products - Serviceguard is welll integrated with HP's other products like the VSE suite and disaster tolerance solutions like ContinentalClusters or Metrocluster.

vi) Maturity - OK this one is pretty subjective, but I happen to think that Serviceguard is simply more reliable and simpler than CRS - others will no doubt disagree.

vii) Other applications - More often than not an application is more than just a database - how do you provide HA for those other components with CRS? This one's also slightly subjective, as CRS does in theory support other apps apart from RAC, but in reality I've hardly ever seen anyone use it for anything apart from RAC. Serviceguard has a rich heritage of proof points with many, many applications.

No doubt there are other reasons, but theres a few to consider.

HTH

Duncan

HTH

Duncan
Court Campbell
Honored Contributor

Re: Service Guard with RAC

SEP,

I have not seen a 10gRAC install on HP-UX that did not require serviceguard and the serviceguard extnesions for rac. I think the note at the end of this page says it all:

http://h20247.www2.hp.com/enterprise/cache/314513-0-0-0-121.html

*Note: Serviceguard and SGeRAC are required components for Oracle9i RAC and 10g RAC on HP-UX 11i servers. Serviceguard is included with the HP-UX 11i Mission Critical Operating Environment, but SGeRAC is ordered separately.

Maybe I am missing something.
"The difference between me and you? I will read the man page." and "Respect the hat." and "You could just do a search on ITRC, you don't need to start a thread on a topic that's been answered 100 times already." Oh, and "What. no points???"
Syed Muqtader Ali
Occasional Visitor

Re: Service Guard with RAC

Syed again .......


My Friends as per my understanding regarding your our conversation is the Major use of Serice guard is to manage NFS and i think this is a correct cuz here in our systems we are using NFS OCR and RAW for database files.

Thanks all
syed
Yogeeraj_1
Honored Contributor

Re: Service Guard with RAC

hi Syed,

also have a look at the metalink note with subject: Raw Devices and Cluster Filesystems With Real Application Clusters
(183408.1)


This document gives an RAC overview and a comparison of raw devices, ASM
and Cluster File Systems across several operating systems.


hope this helps!
kind regards
yogeeraj
No person was ever honoured for what he received. Honour has been the reward for what he gave (clavin coolidge)
Duncan Edmonstone
Honored Contributor

Re: Service Guard with RAC

Court,

That note is, unfortunately not quite accurate. Whilst 9iRAC *had* to use SGeRAC, for 10gRAC, you can if you wish just use Oracle's own clusterware.

HTH

Duncan

HTH

Duncan
Court Campbell
Honored Contributor

Re: Service Guard with RAC

Very cool, Duncan. I did some more purusing and saw some people using clusterware on hp-ux. I was still under the impression that it still only worked on Linux. Now maybe if we do rac on hp-ux we can save a little money. And I stress a small savings.
"The difference between me and you? I will read the man page." and "Respect the hat." and "You could just do a search on ITRC, you don't need to start a thread on a topic that's been answered 100 times already." Oh, and "What. no points???"
Dileep Tallam
Occasional Advisor

Re: Service Guard with RAC

Hai.
We are using SGeRAC A.11.17/A.11.18 in all our installations as we still don't trust Oracle Clusterware completelty. Oracle Clusterware is just not matured. Oracle depended on Vendor Clusterware till Oracle 9i and even in 10g R2 in Tru64 for instance. Also Service Guard provides:

1) HP-UX Packages for Failover of File Systems like Archivelog and RMAN file systems in case of a node-failure. This is used to avoid NFS as NFS has many issues.

2) To have a CFS you have to have SGeRAC on HP-UX. There is no choice.

Also, we don't have any problem with SGeRAC as we have many installations running smoothly with CFS, ASM and also RAW Devices.

Oracle Clusterware only gives two options on Unix Platforms Raw Devices/ASM. Both are having their own issues.

regards,
Dileep Tallam.
kevin_m
Valued Contributor

Re: Service Guard with RAC

We have several RAC 10g R2 instances using raw devices without SGeRAC. ASM, OCR, and CRS are all working fine. Not to say this is the best approach, but it shifts more admin responsibility to the DBA's. Each node has a separate Oracle application home since the binaries are not clustered. I also implemented APA for redundancy on the interconnect/heartbeat network since OCR can only utilize one interface. All the servers are HP-UX 11.31 but the same configuration may apply to prior releases as well.

Kevin