[progress Communities] [progress Openedge Abl] Forum Post: Re: Io Response Discussion

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ChUIMonster

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1) The Furgal test is a test of UNBUFFERED WRITES. Copying a file is a test of *buffered* writes. The disk subsystem is free to lie to you about whether or not the disk has actually written the data. And disk subsystems lie like politicians. This is the kind of IO that Progress does when writing to the BI file. It is very important when determining what to expect for *transaction* throughput. 2) The ProTop ioResponse metric is a test of random disk reads. This is what happens when data is not in your -B cache. It tells you how well your disk subsystem can be expected to respond when you are *reading* data. 15.3 seconds is pretty bad. It is not unusual for a SAN. But, as I have been saying for years, SANs are not there to make anything go fast. There is no such thing as a "high performance SAN". There are only SANs that are not quite as bad as other SANs. The Linux patch would, of course, make lots of sense but that's another discussion ;)

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