Gee, it probably depends on the cache, mdc, number of channels,
type of channels, number of logical devices and software doing
the I/O. And number of engines doing I/O.
Is it old channel, fiber channel or escon?
If a channel can handle 15MB/sec (wag) and you've got 100 of
them, do you know anything useful?
There are installations that page externally more than 5000
per second, and that's just paging.
The answer to your question is probably "enough".
(I think I understood you turned down the offer of our
mailing list - so won't get the next newsletter that talks
about dasd performance, bummer....)
>
>
>What SHOULD you get on a modern mainframe?
>
>From: John Summerfield <[EMAIL PROTECTED]>
>
>> Blindly, your bottleneck is DASD I/O....
>>
>> Look at your dasd performance, your cache statistics, your
>> MDC Cache hits/misses, your wait states for your samba servers,
>> channel utilization, type of channels, number of logical devices,
>> and queues. And what is your CPU utilization? page rate?
>> ("Seem to be OK" often isn't....)
>>
>> 20 MB/sec is about 5,000 I/O per second assuming 4K Blocks. How
>> many logical devices? You are likely seeing very high connect
>> times due to linux chaining I/O together, and 100% device utilization.
>
>--
>Cheers
>John Summerfield
>
>Microsoft's most solid OS: http://www.geocities.com/rcwoolley/
>
>Note: mail delivered to me is deemed to be intended for me, for my disposition.
"If you can't measure it, I'm Just NOT interested!"(tm)
/************************************************************/
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Velocity Software, Inc Mailing Address:
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