Oracle 10G RAC & Continuous Access EVA

[Joseph Salzer_3]

Hi all,

We have a customer that is looking to implement Oracle 10g RAC on a new SAN. They are looking for an active/active solution, so basically if they lose a storage array, the nodes can still access the data from another storage array. We've proposed two EVA8000s with Continuous Access to replicate the data between the two arrays. All though I am familiar with CA, I am not too familiar with Oracle 10g RAC.

Is what the customer trying to do achievable with Oracle RAC and CA EVA?

Thanks

[Joseph Salzer_3]

I forgot to add, that both EVAs will be housed in the same data center with two fabrics (1 switch per fabric).

Thanks

[Ivan Ferreira · Accepted solution]

No, Continuous Access Wont provide the solution requested. Continuous Access works in a active/passive mode, so, if you loss a storage, you must perform a manual failover to access the data replicated to the other storage.

To achieve what the client wants, you don't need replication at storage level and the client must use Oracle ASM to replicate the data between the storages.

[Joseph Salzer_3]

Ivan,

Thanks for the reply. I was aware the the array failover using CA would be a manual process. I am not a DBA, and I had never considered ASM. I am not too familiar with ASM, but it is my understanding that it "virtualizes" storage into disk groups, essentially creating a pool of disks. Does it have replication funtionality? If you put both EVA's under ASM control, wouldn't both appear as a single entity? Would the failure of one EVA, cause data lost or disruption?

Thanks again for your help, and any other feedback is greatly appreciated.

[Ivan Ferreira]

>>> Does it have replication funtionality?
Yes.

>>> If you put both EVA's under ASM control, wouldn't both appear as a single entity? Would the failure of one EVA, cause data lost or disruption?

You will present two RAW units to Oracle, one from each storage, ASM will handle (in his way) the redundancy. If you loose one storage, data will remain available and consistent.

[SSwadesh]

I m not a DBA neither i don't have much knowledge on Oracle. But i beleive wht u want to acheive is seemless failover between the EVA and simultaneous failover of the host machines. Now data replication across eva can be acheived by CA. Host failover can be acheived by Cluster Extension Software which is a kind of a integration between your cluster and CA. See the link below:-

http://h18006.www1.hp.com/products/storage/software/ceeva/index.html

For HP UX this software is called Metro Cluster

[SSwadesh]

Adding to above, if u have syncronous replication across eva then there should not be any data loss

[Bryan Rooney]

Joeseph -
We're currently building what you are describing, with the exception that our EVA8000s are geographically separted via sonet ring (13 km one side, 17 km on the other side). ASM will be handed container(s) from each EVA to make up +ASM diskgroup(s). Luns within each diskgroup need to be the same size and the disks making up the lun need to be of the same disk peformance. ASM will handle the mirror (normal, not external setting) across the separate EVAs and the EVAs will handle lun reduncancy. ASM will allow you to hand the diskgroups to all of your RAC Instances. You will want to go over the data on this site thoroughly:

http://h71028.www7.hp.com/enterprise/cache/429462-0-0-0-121.html

I've attached a PDF on backups with ASM and EVA snapshot/clone functionality.

Reagrds,
Bryan

[Alejandro Revert]

hi all,
we are actually trying to do the same. We have got a three node RAC in one site with ASM and EVA8000. So we are going to move one rac node two a site b, with an eva 4000. the problem is if we use asm mirrorin or continuos access for data replication.
with CA i hoe that in the case of failover you have to mount in ASM manually disks in the EVA4000. but, does anybody know how to do it in ASM ¿? And also if CA is replicating in SYNC mode database will be able to recover ?
what abour ASYNC CA replication , database will be able to recover ?
is there any certification matrix for RAC an CA SYNC and ASYNC and ASM ?

[dlabarthe]

anybody got informations about that ?
so if i understand, it's better to use the ASM replication solution instead of the CA ?

regards,

David L