I am new to ASM world....can you please give your valuable suggestion on below topic.
What is the best practice for online redo log files ? I read it somewhere that oracle recommand to have only two disk group one for the all DB fils, control files online redo log files and other disk group for recovery files, like mulitplex redo file, archive log files etc.
Will there be any performance improvment to make different diskgroup for online redo log (separate from datafiles, contorl files etc) ?
I am looking for oracle document to find the best practise for redo log (peformance) on ASM.
Please share your valuable views on this.
ASM is only a filesystem.
What really count on performance about I/O is the Storage Design i.e (RAID used, Array Sharing, Hard Disk RPM value, and so on).
ASM itself is only a layer to read and write on ASM DISK. What mean if you storage design is ok ... ASM will be ok. (of course there is best pratices on ASM but Storage must be in first place)
e.g There is any performance improvement make different Diskgroup?
Depend...and this will lead to another question.
Is the Luns on same array?
If yes the performance will end up on same point. No matter if you have one or many diskgroup.
Comparing ASM to Filesystem in benchmarks (Doc ID 1153664.1)
Your main concern should be how many IOPs,latency and throughput the storage can give you. Based on these values you will know if your redologs will be fine.
It might worth adding that ASM unlike any other file system or storage solution knows about Oracle database files and uses file templates to optimize the striping size of redo logs, control files, etc. Since ASM is not RAID, it can use a variable striping size for data and dynamically re-size storage space online without having to rebuild and reinitialize data volumes. The number of disk groups does not affect performance, but rather the number and physical location of the underlying devices that create a disk group, as mentioned in the previous response. ASM data redundancy is accomplished between disk failure groups. By default each device is a failure group.