Mounting multiple versions of BeeGFS at the same time

If you have multiple instances of BeeGFS file systems with different versions and need to access them from one client machine at the same time (for example during upgrades), you can use the beegfs-client-compat package. This provides a separate kernel module, allowing to mount the file system of the other version at the same time.

Client

Suppose a client machine is running version A and now shall also access a file system running version B. Install the beegfs-client-compat package from the BeeGFS repository of version B. For example, a BeeGFS version 6 compatibility client:

wget https://www.beegfs.io/release/beegfs_6/dists/deb9/x86_64/beegfs-client-compat_6.18-debian9_all.deb
dpkg -i beegfs-client-compat_6.18-debian9_all.deb

Then the kernel module needs to be build:

$ /etc/init.d/beegfs-client rebuild

This will rebuild both kernel modules.

Node: The init.d script currently does not load the legacy version of the module automatically. We need to do this manually:

$ insmod $(find /lib/modules/$(uname -r) -name "beegfs-*.ko")

To make this persistent, add the module to /etc/modules.

Then we need a configuration file for the compatibility client. The best is to copy an existing one from somewhere, since the options might have changed between versions. Place it here: /etc/beegfs/beegfs-client-compat.conf Edit it, and change the connClientUDPPort to avoid conflict with the other client instance.

Then create an additional mount point, for example /mnt/beegfs_compat and add it to /etc/beegfs/beegfs-mounts.conf (replace versB with the other version number, for example v6):

/mnt/beegfs /etc/beegfs/beegfs-client.conf

# The mountpoint for the old version (versB)
/mnt/beegfs_compat /etc/beegfs/beegfs-client-compat.conf beegfs-versB

Note that the file system type of the compatibility system must be explicitly specified as the third argument in the line.

Finally, restarting the BeeGFS client service will build and load the additional compatibility kernel module and mount both file systems.