Red Hat Bugzilla – Bug 487986
autofs should always read file maps
Last modified: 2009-09-03 10:20:48 EDT
Description of problem:
At start autofs tries not to load an entire map into the internal
cache unless it has to. For maps that do get loaded into the
cache it relies on checks to work out if a map is up to date
in order to trigger a map read. This is fine for maps that can
do direct key lookups but file maps need to do a linear search
through the file when locating an entry for a key. For large maps
this can be a huge overhead.
autofs should always load file based maps at start and make use
of the map file mtime to discover if the cache needs to be
This issue has been fixed in the latest autofs package
I've been unable to devise a way to test this within RHTS.
However, when running the tests in our of battery of regression
tests I found (and fixed) several regressions that had been
introduced by the change.
So verifying this change amounts to autofs passing those existing
regression tests is is supposed to, which is pretty much all of
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Previously, autofs would not always read file maps. If a map had been loaded into cache, autofs would rely on checks to determine whether the map was up to date before reading the map. Because file maps require a linear search through the file, large maps consume significant resources to process. Now, autofs automatically loads file-based maps when it starts, and uses the map file mtime parameter to detemine whether the cache needs to be refresed. This avoids the processing overhead of checking a map before deciding whether to load it.
An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on therefore solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.