SAN Storage performance - data distribution and key figures

[ddellaert]

Has anyone got a configuration with oracle data warehouse sitting on Sun SAN Storage
I have two questions for you.

1. When using oracle on SANdisks, is it still usefull to distribute datafiles over distinct SAN mountpoints or should SAN take care of distributing data

2. Our average elapsed time for a scattered read is 26 Mb per seconds.

I calculated this from de (level 8) wait trace as:
(BLOCKS*blocksize/1024)/Sum(ELA/1,000,000)
=> (38,091*16/1024) / (22,780,281/1,000,000)
= 26.13 Mb/second
where:
ELA = elapsed time for scattered reads (ela in microseconds)
BLOCKS = p3 for the scattered read event
our blocksize is 16k and we multiblock_read_io_count=64 at a time.

If this calculation is correct, it seems rather slow to me but I cannot prove this.
Has anyone got some key figures or experience to back my gut feeling

Thanks for any feedback
Have fun in 2006.
Dikkie

 

[comtec17]

1. SAN is the connectivity between storage and host and has no control of the distribution of data. It is still recommended and always will be to keep the LOGs and Datafiles seperate.

2. This calculation depends on the type of HBA's, type of disk storage on the other side, cache settings on the array, make and models of disks, etc. There are a number of scenarios that need to be mathmatically calculated and a number of performance counters to look at.

 

[ddellaert]

Thanks for the reply.
I realize that the calculation of "expected" throughput depends on all these things. But from a user perspective, I know my readspeed, and I am wondering wether this is normal for an average SAN system, low for an average SAN system, or whatever.
Any thoughts on that.
Thanks

 

[comtec17]

Normal for an average system, it is not normal for a properly working, designed, and configured system.