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kkhayer's avatar
kkhayer
Level 2
14 years ago

Using "Unbuffered" (Direct I/O) with RAC + SFRAC

Veritas Storage Foundation for Oracle RAC 5.1 Oracle RAC 10.2.0.5 Currently, MountOpt="mincache=direct" is not set in main.cf. My questions here are: - Would it make a difference in write...
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  • ScottK's avatar
    ScottK
    14 years ago

    Since you are using SFRAC & Oracle RAC, I/O should be going through the ODM interface (assuming everything is properly configured).

    ODM is an API between Oracle and the Veritas File System. I/O going through ODM is not buffered, nor locked by VxFS. This allows Oracle to manage both memory and locking, which increases performance in most cases. The mincache setting does not affect ODM, but I/O going through normal read/write calls.

    If you have files outside of Oracle, those are the ones that would benefit.

ScottK's avatar
ScottK
Level 5
14 years ago

Since you are using SFRAC & Oracle RAC, I/O should be going through the ODM interface (assuming everything is properly configured).

ODM is an API between Oracle and the Veritas File System. I/O going through ODM is not buffered, nor locked by VxFS. This allows Oracle to manage both memory and locking, which increases performance in most cases. The mincache setting does not affect ODM, but I/O going through normal read/write calls.

If you have files outside of Oracle, those are the ones that would benefit.