Re: Oracle on a NetApp

Michael Karafotis wrote:
>
> Okay everyone,
>
> Could someone explain to me why it is bad to store oracle datafiles,
> redologs, and control files on a Network Appliance?
>
> As I understand it the argument against doing such a thing is
> consistency of the redo logs. Oracle needs to be sure that data is
> actually written to the device before it can continue on and clear the
> redo buffer. My understanding of NFS V3 and V2 for that matter is that
> all writes are by default synchronized (in other words dirty writes or
> cache writes do not return a write success, only a stable write to the
> device does.) If this is the case why is it taboo to run the database
> off a FAST, RAID 5, backend (private subnet) NFS server like a Network
> Appliance.
>
> All help appreciated.
> Michael
>
> ---------------------------------------------------------------
> Okay everyone,
>
> Could someone explain to me why it is bad to store oracle datafiles,
> redologs, and control files on a Network Appliance?

  If datafiles and redologs are stored on the same disk, DBWR and LGWR (or CKPT) will contend for the disk I/ O when a checkpoint is issued.

  If all datafiles are stored on the same disk, the SYSTEM datafiles and other datafiles will also contend for disk I/ O.

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Name   : Lun Wing San
Title  : Oracle Application Developer of Hong Kong Productivity Council
         Oracle Database Administrator and System Administrator of QRC
Phone  : (852)27885841