Re: dedicated spindles and Oracle

Are you using ASM? What kind of database? OLTP or DW? What is your performance goal? IOPS or IO/ Bandwidth, and how much?

I can tell you that for the DW benchmarks I done I use one ASM disk group for everything (data/index/control/redo). This is the easiest and nearly the best performing way. You may wish to have more disk groups for archive or flash back, etc. depending on your specific requirements. Separating index and data is more a manageability thing than performance IMO, there isn't really any reason they can't share the same spindles. I've also never heard of a requirement that needed control files on dedicated spindles.

As far as LUN size: ask the storage admin for the best performing size. This will vary by setup, but usually consists of full disks from different controllers/paths and RAIDed together and presented to the host as a single LUN. For example, in storage arrays that use quadrants, a 2+2 RAID10 works well, taking a physical drive from each quadrant. These LUNs are then ASM disks in your ASM disk group.

On 9/15/07, ryan_gaffuri_at_comcast.net <ryan_gaffuri_at_comcast.net> wrote:
> I was talking to an Oracle guy who also works with SANs. This is what he told me. For optimal performance do the following
>
> 2 redo log groups each with dedicated spindles
> 2 archive logs each with dedicated spindles
>
> data data files have their own dedicates spindles with several lines and spread the data files out
> index data files do the same thing but have their own dedicated spindles
>
> control files can be placed on the same spindles as data files, however, check point activity on systems with large numbers of data files especially when doing hot backups may require control files having their own dedicated spindles.
>
> What is your opinion? Is there any way to estimate a good starting point to test LUN sizes for performance? Not sure what sizes I should ask for to begin my performance tests. I was thinking of running bench marks with several different sized LUNs.
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Regards,

Greg Rahn
http://structureddata.org
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