Mirror volumes solution for Oracle DB

[fitz123]

Hi everyone!

I am very tired of trying to do it.
We have 4 node (2xp4300) and 2 servers(RHEL 5.5 on hp DL580 G7). 4 nodes and 2 servers in same subnet. CMC (win 2008 x64 on ESXi) and FOM(on the same ESXi) in another subnet . I've installed all required software, initialized iSCSI sessions, but I can not set up the Application Aware Manager (have a "could not discover the controlling application server" error).  And did not understand why needed FOM, except for migration Volume??

Has to be made fault-tolerant array for the Oracle database.

I think the best option - it is a 2 network raids (2 nodes raid 0 = 1 volume and 2 other nodes Raid 0. 2 Volumes = Raid 1). But, as I understand - it is not possible.
How else can I do it with minimal losses? Please, help me.

Best regards and sorry for my english.

[Dirk Trilsbeek]

you don't need two separate network raid volumes. A single network raid 10 volume is all you need to make sure you are protected from partial storage failure.

A Lefthand Volume with Raid 10 mirrors all data on two concurrent nodes within the cluster. If a node fails, the data is still available. If two nodes fail and they are not directly adjacent, the data is still available, at least if you have a quorum, either by using a FOM or a virtual manager. You will just have to make sure you don't introduce a single point of failure within your network infrastructure (single switch between sites etc.).

A failover manager is required to have an uneven number of members in a management group. A group with 4 nodes, located in 2 sites, will completly fail if the connection between the sites fails - even if at least one of the sites could still be running. A failover manager, usually located in a separate third site makes sure that your cluster will stay online when that happens.

If you need multipathing, you will have to locate each 2 nodes on different subnets and assign two VIP addresses to your cluster.

[fitz123]

Hi Dirk,

Yes!! "Not directly adjacent" - this is the secret! it works, this is great!

But there is still a problem - does not work Application Aware snapshot. I can create Application Aware Snapshot (AAS), but then i have a "AAS has failed. Reason: Shadow copying the specified volume is not supported."
I have started "Win Shad Copy", "HP VSS" services and connected to the Volume by MS iSCSI initiator. Then i've created AAS. But it doesn't work!
That i missed?

Thank for you answer. It's really helped me!

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It seems like I've solved this problem! In my case solution was http://adsm.org/forum/showpost.php?p=24633&postcount=3

BUT! 

I understand, Application Aware Snapshot is only supported with Windows systems? In our case, the initiator is RHEL and AAS unsupported..