Performance monitoring?

[pll at lanminds.com]

Hi,

Does anyone know of any utilities which can dig into disk drive 
performance?  I'm looking to discover the "disk busy" time, i.e., 
what percentage of time is the disk off doing something, such that 
requests to the disk are blocked.

I've looked at: sar and iostat, but they don't provide this metric.  
All I've found so far is number of read or write requests made per 
second, and ([k]bytes|blocks) per second read or written, and 
transfers per second issued to the device.

Unfortunately, there's not much to connect these metrics.  read/write 
requests and transfers per second only tell me that a transaction was 
requested, but not the size of that transaction.  There's also 
nothing which tells how many transactions were capable per second 
compared to those which succeeded.

The [k]bytes or blocks per second read or written metric suffers from 
the same problem in that I can't correlate them to anything which was 
actually requested. So, I have one set of metrics telling me that 
something was requested, but not the size of the request, and another 
metric telling me how much data was transferred, but nothing telling 
me how much was requested.

Any ideas?

Thanks,


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Seeya,
Paul
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