Adam Goryachev wrote:
>
> If I found an idle system that I could create various FS on, with
> various parameters, what series of tests should I run to compare 'real
> world' backuppc performance?
One relevant one would be from a benchmark called 'postmark'. It was
originally available from the NetApp people but I think it has been
packaged for debian and the source should still be available there. It
tests the speed of creating and deleting a lot of small files so it
should tell you how fast you can do directory operations.
> ie, as was noted, creating 10,000 hardlinks could be entirely cached and
> therefore does not represent real performance, but if we created as many
> hardlinks as possible for 30 minutes, and then compared the number of
> hardlinks, would that be a better test?
A hardlink itself is just like any other directory entry.
> What about when the filesystem
> becomes more full, or after it becomes more fragmented, etc....
> If we could come up with a series of commands which can be reasonably
> easily repeated, then it is simply a matter of finding some idle
> hardware to run the tests on.....
The part that is probably impossible to emulate is the way links
eventually end up being to files whose contents are all over the place.
Most file systems try to allocate space so that the names in the same
directory, the inodes used, and the data are as near as possible to each
other, but backuppc will end up with directories full of links pointing
to inodes and data that weren't allocated together and have essentially
random locations on the disk.
--
Les Mikesell
[EMAIL PROTECTED]
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