Re: Cache Hit Ratio from system views

"Ana C. Dent" <anacedent_at_hotmail.com> wrote in message news:xT8xi.82911$kK1.41582_at_newsfe14.phx...
> "Bob Jones" <email_at_me.not> wrote in
> news:eB8xi.1326$i75.244_at_newssvr19.news.prodigy.net:
>
>>>> Why is BHCR meaningless? The answer should be short and simple. I
>>>> want to hear your opinion.
>>>
>>> One can not prove a negative.
>>> Where is your proof BCHR is a reliable indicator of GOOD performance?
>>
>> BCHR alone does not tell you about overall performance. It simply tell
>> you the disk I/O percentage. It is an indicator, a very meaningful
>> one.
>>
>
> HUH? BCHR does NOT come close to measure disk I/O;
> so by what stretch of imagination does it measure "I/O percentage"?
> BCHR measure RAM activity says absoluting NOTHING about disk activity.
>

Allow me to clarify, the percentage of reads from disk.

> You said, "It (BCHR) is an indicator, a very meaningful one."
>
> Please answer each below as a standlone measure of performance
> System A has a BCHR of 22. What does it indicate?
> System B has a BCHR of 42. What does it indicate?
> System C has a BCHR of 62. What does it indicate?
> System D has a BCHR of 82. What does it indicate?
>

22% of reads are from memory.
42% of reads are from memory.
62% of reads are from memory.
82% of reads are from memory.

I hope you are trying to make a point here. Received on Thu Aug 16 2007 - 23:28:26 CDT