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Run a few tests and you will find all sorts of interesting cache and window
bottlenecks. A while back I did extensive testing on RAID systems to learn
actual performance of the installed systems. Real performance varied by
a factor of one thousand! Unless you have some knowledge of the
underlying file system IO parameters, you cannot measure any real network
traffic speeds for file copy. Note that on Windows systems, IO performance
drops off by a factor of 100 as you approach fullness on the file system.
Checking performance between 90% and 99% full will give you meaningless
numbers. Even above 80% it starts to get bad.
Use dd if=/dev/zero of=some_file bs=x count=y for a wide variety of x and y.
Then do the inverse test of reading.
Then do the same sort of logic with nc for a remote system -- no disks.
Then do the same sort of test with a combo of nc and dd to test real
io and network speeds combined.
Finally do the 4-way test with dd and nc at both ends with and without
real files with a variety of block sizes for the transfer at the dd level
and the nc level, and vary the transmission prototocol.
For comparison, use NFS and use dd for remote mounted systems.
Then use a few tests with RAMdisks.
All this is really easy to do on Unix, linux and OSX systems, and not so
bad under Windows using SFU.
bottlenecks. A while back I did extensive testing on RAID systems to learn
actual performance of the installed systems. Real performance varied by
a factor of one thousand! Unless you have some knowledge of the
underlying file system IO parameters, you cannot measure any real network
traffic speeds for file copy. Note that on Windows systems, IO performance
drops off by a factor of 100 as you approach fullness on the file system.
Checking performance between 90% and 99% full will give you meaningless
numbers. Even above 80% it starts to get bad.
Use dd if=/dev/zero of=some_file bs=x count=y for a wide variety of x and y.
Then do the inverse test of reading.
Then do the same sort of logic with nc for a remote system -- no disks.
Then do the same sort of test with a combo of nc and dd to test real
io and network speeds combined.
Finally do the 4-way test with dd and nc at both ends with and without
real files with a variety of block sizes for the transfer at the dd level
and the nc level, and vary the transmission prototocol.
For comparison, use NFS and use dd for remote mounted systems.
Then use a few tests with RAMdisks.
All this is really easy to do on Unix, linux and OSX systems, and not so
bad under Windows using SFU.
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