[Linux-cluster] May I turn on direct I/O and/or async I/O when using GFS as the cluster file system for Oracle9i RAC?

Wendy Cheng wcheng at redhat.com
Mon Feb 13 18:54:42 UTC 2006

Thai Duong wrote:

> Hi Wendy,
> Thx for the information. I'll turn on direct I/O on my system. Do you 
> have any information about how many percent I should gain in term of 
> I/O performance when turning direct I/O on in general and with Oracle 
> RAC in particular?
Our performance group did pass the numbers around sometime ago - the 
gain seemed to be quite positive but I don't remember the details. On 
the other hand, do remember this is not a frequent execution code path 
so try to take the switching steps slowly (i.e. make sure you have 
backup plan, etc, particularly on GFS 6.0 system).

-- Wendy

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