February 20, 2019

Using the InterMezzo Distributed Filesystem - page 5

Getting Connected in a Disconnected World

  • August 12, 2002
  • By Bill von Hagen

All of the systems on which you want to run InterMezzo must have InterMezzo support in the kernel, either compiled into the kernel itself or available as a loadable kernel module (LKM). (A pre-compiled InterMezzo LKM is provided with the out-of-the-box kernel for some Linux distributions, such as Red Hat 7.3.) Built-in InterMezzo support is available in all kernel versions newer than 2.4.5, but can be added to many older kernels by applying patches available on the Web or by building an InterMezzo module from source. This article focuses on activating and using InterMezzo in Linux 2.4 kernels that contain InterMezzo support.

You can determine if an InterMezzo LKM is already available for your kernel by issuing the command "insmod intermezzo" as the root user. If an InterMezzo module is available, this command will displays the message Using XXXXX, where XXXXX is the full pathname of the InterMezzo module. If no InterMezzo module is available, you'll see a message like insmod: intermezzo: no module by that name found. If no LKM is available, there is no easy way to determine if InterMezzo support is compiled into your kernel other than trying to mount an InterMezzo filesystem, as described later in this section. If you see the message mount: fs type intermezzo not supported by kernel, you will need to build a loadable kernel module for InterMezzo, as described in the next paragraph. If you could successfully load the InterMezzo LKM, you can skip the next paragraph and proceed to

If your kernel does not already contain active InterMezzo support and no InterMezzo LKM is already available, you will need to have installed the kernel source code for the version of the kernel that your system is running. If installed, it should be located in a subdirectory of your /usr/src directory that has the same name as your kernel version. If it is not installed, a package containing the kernel source code for your Linux distribution should be available on your distribution disks.

Once you've located the kernel source code, execute the command make xconfig to display the Linux kernel configuration's X Window system-based kernel configuration mechanism. The InterMezzo option is located in "File Systems" panel's "Network File Systems" panel. Select "m" beside the "InterMezzo file system support (experimental, replicating fs)" entry to build this as a loadable kernel module, and exit from xconfig, saving your changes. You can then execute the make dep, make modules, and make modules_install. You will need to do this on both your client and server systems. Once the module is compiled and installed, you can then use the insmod command described earlier in this section to verify that the module compiled correctly and could be correctly installed on your system.

If you don't have a spare partition on your client system(s) that you can dedicate to InterMezzo, the kernel running on each of your systems must also have support for the "loopback device". Loopback support is only necessary if you do not have a spare partition on your client system. You can build loopback device support as a module by by selecting "m" beside the "Block Devices" panel's "Loopback Device Support" option in make xconfig. If you need to add loopback device support to your kernel, you should do this at the same time that you selected building the InterMezzo module, and then build both modules at the same time by using the make commands that were described earlier in this section.

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