CernVM-FS Known Issues

Mounting might take very long time

This issue occurs if access to /dev/fuse is restricted to the fuse group and users and groups are maintained in large LDAP directories. As part of the mounting, CernVM-FS mount helpers drop privileges from root to the cvmfs user and, if necessary, to the fuse group. In order to do so, the system has to search for the group membership of root in the fuse group.

As work-around, you can add the root user explicitly to the fuse group in /etc/group. In that case, the system stops successfully in the local search and does not query LDAP.

Thanks to Steve Traylen for pointing out the issue and the work-arounds.

Automount hangs when mounting a repository

There is a known deadlock that can happen in older versions of RHEL5 autofs ( It has been fixed as of RHEL 5.7.

CernVM-FS does not mount because of dangling /etc/mtab~ files

There is a known problem in older versions of the umount utility that can result in the dangling lock files for /etc/mtab ( These dangling lock files prevent CernVM-FS from being mounted again. For RHEL, the problem is fixed as of util-linux-2.13-0.59.

Running Fortran programs fails with "read-only file system" error

There is a bug in SL6 kernel versions between 2.6.32-279 and 2.6.32-358.11 (not including) when files are opened with specific flags from a read-only file system such as CernVM-FS (see here and here for details). Such flags are in particular used by Fortran programs. Either upgrade to the latest SL6 kernel or (for CernVM-FS >= 2.1.12) set CVMFS_MOUNT_RW=yes in /etc/cvmfs/default.local. This tells the operating system that CernVM-FS is a read/write file system. Of course, any attempt to actually perform a write will still fail.

CernVM-FS fails to resolve host names

Certain versions of SL5 leave /etc/nsswitch.conf with restricted permissions 0600 (see here for details). CernVM-FS drops root privileges before the first network access. Access to /etc/nsswitch.conf is necessary though to resolve host names. The problem typically shows as a failure to mount any repository.

CernVM-FS fails to compile at "building libtbb"

Compiling CernVM-FS fails like

Building libtbb...
build/ *** "" is not supported. Add build/.inc file with os-specific settings .  Stop.

This can happen if the environment variable OS is not empty. As a workaround, unset the OS variable during compilation.

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