AIX Mirror Write Consistency

Does anyone have any experience with turning off MWC (Mirror Write Consistency)
on AIX with Oracle? My guess is it is ok. A note on metalink said it is a requirement
for parallel server, and a small document I found (which I could post)
- says the following:

"Data Integrity :
You can only have problems (by turning it off) if you are using a program which can read
data for which no completion stats was given for the previous write.

Even without mirroring, if a system crash occurs whilst a write is outstanding there is not a lot you can say about the data area on the disk when the system comes back. It could be old data or new data or some mixture of some other data entirely.

Relational databases use a log file to allow them to recover from a crash so, proviced the log file algorithm allows for this condition, there should be no problem. You should check with your app vendor to see if there recovery algorithm for a system crash can cope with mirror write consistency turned off. I suspect that most can. "

Oracle does not even finish a commit until it has received that write has completed no?
So it should be ok I think. Unfortunately, I will need an official answer from Oracle I
think. Turning it off can give a huge performance boost I read.

Any thoughts?
- Dc.
Received on Thu Dec 23 1999 - 13:49:28 CST