Re: Is my Oracle Server issuing more IO than it can handle

From: Harel Safra <>
Date: Tue, 07 Dec 2010 21:12:42 +0200
Message-ID: <>

This calculation is only true if you work with disk drive directly attached to you servers, and even then when there is no cache in the raid controller.
Once you start working with central storage systems things like cache size, i/o distribution and disk sharing start to come into play.

For example, our EMC dMX4 storage has 96GB of cache. If your database is smaller than that (and nothing else uses the cache in this example) you could get very high throughput even with a single physical disk.

Do you know which kind of storage you use? Is you system the only system attached to it?

Harel Safra

On 07/12/2010 20:05, Oracle Dba Wannabe wrote:
> Do any of you have any thoughts w.r.t to question 1 - whether those
> calculations can be representative of the disks i may need.
> thanks
> ------------------------------------------------------------------------
> **1. Is there someway from awr that I can determine that the Oracle
> server is issuing more IO than the storage system can handle for example:
>> Physical reads: 954.74 16.68
>> Physical writes: 418.89 7.32
>> Phy Reads + Phy Writes = 1372 IOPS
>> Can I then say that if each disk can do 100 IOPS, that the
>> storage system should at least have 13 Disks? (13x100 IOPS)? Or
>> is that an over simplification?

Received on Tue Dec 07 2010 - 13:12:42 CST

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