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Re: [Linux-cluster] gfs2 v. zfs?



Rafa Grimán wrote:

Yes that is true. It's a bit blurry because some file systems have features others have so "classifying" them is quite difficult.

i'm amazed at the conversation that has taken place by me simply asking a question.

*Thank You* all for all of this info!

we've traced the response time slowdown to "number of subdirectories that need to be listed when their parent directory is enumerated".

btw, my usage of "enumeration" means, "list contents". sorry for any confusion.

we've noticed that if we do:

ls -lhad /foo
ls -lhad /foo/stuff
ls -lhad /foo/stuff/moreStuff

response time is good, because , but

ls -lhad /foo/stuff/moreStuff/*

is where response time increases by a magnitude, because moreStuff has ~260 directories. enumerating moreStuff and other "directories with many subdirectories" appear to be the culprits.

for now, we'll be moving directories around, trying to reduce the number of nested levels, and number of elements in each level.

in human interaction there is a rule: as the number of people interacting increases linearly, the number of interactions between the people increases exponentially. is it true that as the number of nodes, "n", increases linearly, the amount of metadata being passed around / inspected during disk access increases geometrically? does this "rule" apply? or does metadata processing increase linearly as well, because the querying is all done by one node?

thanks again - what a group!
yvette


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