[CentOS] automounted filesystem appears empty on first reference
halbert at everyzing.com
Thu Oct 4 03:33:47 UTC 2007
I have an odd automount problem. The first time I look in an automounted
filesystem (when the mount is requested), it is empty; the second time
it is not. Moreover, I only see this behavior on Centos 4.x systems, but
not on Centos 5.0 systems going to the same fileserver. Here's an
example, with some details simplified to clarify. In this example,
fileserver1 is exporting fs1.
centos4$ /bin/ls /mnt/fileserver1/fs1 # first time, directory
centos4$ /bin/ls /mnt/fileserver1/fs1 # second time, I see the
I don't see this on Centos 5, which comes with a new (v5.x vs v4.x)
version of automount:
centos5$ /bin/ls /mnt/fileserver1/fs1 # I see the contents
right away, on the first try
I watched the logs on fileserver1, and automount request is logged
immediately after the first ls prints nothing.
The automount maps are stored in ldap. The Centos4 and Centos5 systems
are referencing the same maps. The entry in auto.master for fileserver1
(for cn=/mnt/fileserver1) is:
and in auto.fileserver1 is (for cn=*):
At first I thought it had to do with the --ghost, but I took that out
and adjusted things and still had the same problem. It is completely
reproducible if I umount the automount between tries.
Any idea what is causing this? I have been unable to find a
similar-sounding problem, even with extensive Googling. Why does the
first automount appear to be asynchronous, with some kind of race
condition, and the second is synchronous? I even see a little hesitation
on the centos5 box before ls prints the directory contents, so it
appears to be waiting for the automount to complete. All the Centos 4
and Centos 5 boxes are current with "yum update".
This problem is causing failures on some of our applications because
they don't see their data the first time they run, when the automount occurs
We see this across many boxes, and several fileservers (the fileservers
are Fedora Core 5 and 6 machines, for stupid reasons).
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