Sun Cluster 3.x and RAC design issues.
Hi All,
I am in the middle of a rather picky situation. Can anyone tell me if using a global file system( Enabling global via vfstab ) on a cluster running RAC is recommended? I know the effect it has on the interconnect but i am going through lots of debates with my DB admins saying they need them global for flexibality issues and they do not sacrifice that much performance even when using RAC.
Can anyone give me a clear justification to help them change there minds?
Also to make the picture clear we will be using a raw fs for RAC tablespaces with vxvm and CVM enabled but its the other filesystems that they want mounted globally.
How much will this effect performance?
Is there a need for RAC to have access to anything global other then the RAC-dg itself?
[807 byte] By [
N_H_Da] at [2007-11-27 9:19:15]
# 2
I understand but what is the need to have access to the archive from both nodes? If the funcionality exists and in case 1 node goes down the archive fails over to the other wouldnt it be better to not leave a chance for anything strictly needed to go through the interconnects?.
Also when sun says they do no support RAC with a global file system wouldnt the archive and links directories go under RAC installation in this case.
If the directory is global and fails over when the node goes down wouldnt it be slower then if it was local and failing over?
n_h_da at 2007-7-12 22:11:17 >
# 3
Hi,
global filesystems and Oracle RAC is a hot topic. It is not true, that there is no support for global filesystems with RAC. But: you must not use the GFS, that comes with SC3.x but shared QFS. And you have to look what types of files you can put where.
To have all the details have a look at "Table 1? Storage Management Schemes for Oracle Files" in the doc "http://docs.sun.com/app/docs/doc/819-0583/6n30h62v7?a=view". And also have a look at Tim Read's whitepaper "Sun Cluster 3.2 Software: Making Oracle Database 10G R2 RAC Even More Unbreakable " available at www.sun.com/cluster in the spotlight section.
Regards
Hartmut
# 4
Thank you all for the response and I checked the links and have reached a comprimise. Only the offline archive and the links will be global and everything else including any application directories mounted will be local.
Now ill be looking at optimising oracle failover. Id like to see if I can make it untouchable and not just unbreakable. Untouchable in the sense that if one node goes down everything resumes including rman backups and no manual intervension is needed ( editing rman script ). Id also like to compare failing over a local file system and a primary node for a global file system to see which is faster.
Any ideas are welcome and thanks again.
n_h_da at 2007-7-12 22:11:17 >
