Re: FRA f/s block size
- From: Nuno Souto <dbvision@xxxxxxxxxxxx>
- To: oracle-l@xxxxxxxxxxxxx
- Date: Mon, 28 Mar 2011 20:32:19 +1100
Thanks Yechiel. That's my gut feel as well.
The only minor snag I can see is that AFAIK the actual I/O size used by RMAN is
not documented anywhere. If it is doing 512 units in scatter/gather I/O, then
it's virtually the same as 8K blocks - assuming the db is 8k.
Given that it is mostly doing big sequential as you note, it shouldn't matter at
all if the last block gets half-filled in case it's doing 8k block I/O.
Ah, I wish I had in Unix the ability to trace actual raw I/O sizes no matter
what, like I could in the mainframes...
--
Cheers
Nuno Souto
in sunny Sydney, Australia
dbvision@xxxxxxxxxxxx
Yechiel Adar wrote,on my timestamp of 28/03/2011 5:52 PM:
No experience, just a thought.
It is used for big sequential writes and no random reads or writes.
In this case I will used the biggest block I can to minimize the I/Os to the
disk.
The reason we use small blocks is to minimize the redundant data transferred to
memory when you need only one record in the block.
When you write or read whole blocks, in big sets, use the block size that will
minimize I/O.
--
//www.freelists.org/webpage/oracle-l
Other related posts:
