English to Japanese Tech/Engineering Computers: Systems, Networks

I know "churn" means "customers switching from one provider to another provider," but in the following sentences, which is extracted from Description column of a table which describes file servers, it seems to have a different meaning.
Does these "churn" mean "processing" or something else?
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1)“Average” amount of churn with most activity at quarter end. This server has about 100 regular users.

2) Lots of churn, definitely the most active of the file servers


I also found the following two sets of sentences on the Web which might be helpful:

One management cost area where Linux seems to
consistently trump Windows is the cost of managing
security. A big driver for Cedars-Sinai’s switch
to Linux was “the tremendous **amount of churn** we
have on our NT servers,” due to hot fixes,
service packs, and so on, Duncan says. “We did an
analysis of the amount of time we were spending
tweaking NT servers, and it really was kind of
terrifying. We should be able to set up a server
and just leave it alone ? we really got into Linux
from that point of view.”
(http://www.freerepublic.com/focus/f-news/976278/posts)

In the version which supports snapshots, I plan to alter the way the server works. The chains of patches will be kept, but will be managed outside the directory structure. Also, the responsibility for managing the directories will lie with the client so that they can be signed (and also reduce the **amount of churn** on the server when uploading lots of files into a directory.)
(
http://lists.warhead.org.uk/pipermail/boxbackup/2005-April/0...