OCR and OLR - RAC 09

In this video you will learn what is OCR and OLR. These are files maintained by Oracle Clustereware to manage the resources that are to be made available in the cluster across the nodes.
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[@RoccoHubOfficial]

Welcome back sir after long time

[@govind83]

You are awesome Sir.. please add more video for RAC

[@RamkumarSwaminathan]

Thanks.. will do...

[@sachinbs3961]

Sir,
I don't understand the point of having the OCR when all the information to bring a node up is present in OLR. Is it only to hold the intended states of different resources for fault proof management?

[@RamkumarSwaminathan]

OCR is a cluster resource to ensure consistency across nodes, OLR is a node specific resource

[@praveenganesh4708]

Thank you sir
Please share us the cluster startup sequence when you find time

[@RamkumarSwaminathan]

Sure shall do...

[@TheTaushikdasgupta]

Hello Ramkumar,
Videos of yours are really engaging and simple to grab. Can you please let me know if you have any video for cluster startup sequence?
Also, Can you please also make a video on GPNP?
Thanks, Looking forward to your response!

[@9946022950]

Hi

[@sinchanb6737]

Ram, it is a good discussion

[@RamkumarSwaminathan]

Thanks ...

[@anandparthasarathy599]

Sir start some practical sessions as well for12c

[@karteekvarma8155]

A slight correction needed here: None other than the Master Node can write as well as Read, only the Master can read all other partner nodes will also have to relay read via the Master node

[@sanedba8458]

sir would you tell why we use odd number of voting disk ???

[@madhankumarkancharla28]

We must have odd number of disks.
Oracle recommends minimum of 3 and maximum of 5. In 10g, Clusterware can supports 32 voting disks but in 11gR2 supports 15 voting disks.
A node must be able to access more than half of the voting disks at any time. For eg, if you have 5 voting disks, a node must be able access atleast 3 of the voting disks. If it cannot access the minimum of voting disks, then it is evicted/removed from the cluster.
All nodes in the RAC cluster register their heartbeat information in the voting disks/files. RAC heartbeat is the polling mechanism that is sent over the cluster interconnect to ensure all RACnodes are available.

[@sanedba8458]

thq's alot bro u said in 11g 15 --> VDisk in High redudancy ???

[@madhankumarkancharla28]

sane dba exactly high redundancy bro

[@MrTimer402]

sane dba In order to avoid the sliptbraincindrome Oracle recommend to maintain the odd no.of voting disks .. bro

[@ronaknmodi]

Explain about OHASD AND CRSD

[@RamkumarSwaminathan]

Ok, shall work on that...

[@ronaknmodi]

Ramkumar Swaminathan Thank you

[@belowasmelashgebremariam]

Asmelash selam