[Linux-cluster] gfs2 v. zfs?
yvette hirth
yvette at dbtgroup.com
Tue Jan 25 19:34:15 UTC 2011
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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