Re: Number of IOs Per Second

CHANGE USERNAME TO westes wrote:
>
> I need to size a storage system. I know that I will have two tables, each
> with eight million records. I will have 10 users, each of whom will be
> doing complex reports simultaneously, each of which does joins against those
> eight million record tables.
>
> What are some guidelines for best and and worst case, about the number of
> IOs per second that this system will generate? I need to make sure my
> RAID arrays have enough physical disks to satisfy this number of IOs.
>
> If the database is 2 TB in size, what is the desired amount of cache memory?
>
> --
> Will
> westes AT earthbroadcast.com

Your queries won't generate "IOs per sec", they will simply generate "IO". You could imagine a worst case scenario would be a nested loop cartesian join (8m x 8m x size of table A x size of table B). eg 200 bytes per table yields around 2 terabytes of disk read. Hopefully your queries will be better than that :-)

Once you've got a handle on typical IO, and how long the queries are allowed to take, *then* work out what IO's per second you need to achieve the results you need.

After all, a single home PC 400G disk drive could do the job...but might achieve a response time for the queries that you'll be overly happy with :-)

-- 
Connor McDonald
Co-author: "Mastering Oracle PL/SQL - Practical Solutions"
ISBN: 1590592174

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