Re: Oracle performance & bottle necks (redo,rollback and datafiles)

In article <36B1E993.ADE5B99_at_capgemini.co.uk>,   Mike Burden <michael.burden_at_capgemini.co.uk> wrote:
> If one is trying to get oracle to perform at its best where should redo
> logs, rollback segments and datafiles be allocated to.
>
> For example assume it is critical that a mass load must completed within
> a given time frame.
>
> The box has multiple processors (to take advantage of parallelism) and
> uses stripping to get flat out performance for the datafiles. But my
> question is: won't this just shift the bottle next to the redo logs
> (probably not the rollback segments). If the redo logs have twice the
> amount of data being written to them (i.e. datafiles and rollback
> segments) then on a sequential load this will surely be the bottle neck.
> Writing to the redo logs can't be done in parallel, can it? Putting the
> redo log files on to a stripped disk may help assuming archiving is
> switch on (hmmm...I'll think about that one).
>
> Could be really radical and backup the database first then assign the
> redo logs (and rollback segments) to a null device. If oracle reads from
> these files then a RAM drive is an alternative.
>
> The same applies to random updates but in this case the datafile
> processing is slowed down somewhat because of reads, index access etc.
>
> Are there recommendations which state how fast redo logs disks or
> rollback disk should perform when compared to the datafile disks.
>
> Hi,

This is k.v.s.raju, from INDIA.

Log files are more critical in tuning the database . When there are more transactions, there will be more redo for the database. All the redo has to go thelogfiles .So there will be a problem with redo logfiles to write to them.
For this the solution is put the logfiles on a RAW DEVICE (WHICH is more effecient for WRITES ).As we know we are not going to read from logfiles but only writing, u can put on a raw device.

regarding rollback segment files and data files, keep them on a separate disks so that data can be retrived or written on to them simultanesously.
Hope this clarifies u'r doubt

rgds
k.v.s.raju
kvsraju_at_usa.net or kvsraju_at_polaris.co.in

-----------== Posted via Deja News, The Discussion Network ==---------- http://www.dejanews.com/ Search, Read, Discuss, or Start Your Own Received on Thu Feb 04 1999 - 05:11:34 CST