Advanced Partitioning for Glued Linux Installs

Advanced Partitioning for Glued Linux Installs

The standard glued linux installation procedure trades flexibility for ease of use with respect to the allowed disk partitioning. Although you can choice the disk to install on, and can opt to use fdisk to resize partitions, you are still stuck with the basic partioning scheme, wherein

File system Disk partition/slice # FS type Comments
root (/) 1 ext3 /boot and /tmp on this partition
swap 2 N/A  
/usr 5 ext3  
/var 6 ext3  
/usr/vice/cache 7 ext3  
/tmp N/A N/A same fs as root(/)
/boot N/A N/A same fs as root(/)

While the above is fine for most situations, and indeed is quite similar to the set up on other Glue platforms, it can be a problem if you have special needs. E.g. dual booting, spreading the image over multiple disks, or even just maintaining a copy of the original OS in case you want to be able to talk to the vendor if there is a hardware issue. The following discusses how to do some more stuff.

This is not for the faint of heart. Neither Physics nor OIT Glue staff promise that any of this stuff will work. In particular, while this page may help you to install a system in a given way, no guarantees are made that the installed Glue system will be functional. E.g., not all supported filesystems are supported by the AFS client for the cache partition.

The basic procedure is to do the netboot as you would do for a normal install, but choose the advanced partioning option during the install. You then can partition your drive or drives with fdisk, as per normal. After formatting, you will be brought into an editor screen wherein you can create a config file which instructs the glueinstall which partition is which, etc. as described below.

  1. Netbooting: this part is the same as in the Glue documentation. Choose the correct installation option, and answer yes when it asks if you want advanced partitioning option.
  2. Creating the partitions: again, basically the same as standard. The glueinstall script will launch fdisk on the drive you requested for installation. I beleive it also allows you to run several times on different disks if desired. You should continue to use the OIT recommendations for partition sizes; namely Please note that the Glue system will eventually be using volume labels named after the mount points for mounting the partitions. The script will label the specified partitions appropriately, but it currently does not check to see if any other partition is using one of these labels. You should make sure nothing is labelled at this point. (This problem is most likely to occur if some partitions formerly had a linux distribution on them).
  3. Configuration file: After you are through with fdisk, glueinstall will throw you into an editor with a sample (commented out) config file. You must edit this file to inform the code which partition it should use for which filesystems. It consists of ASCII text, one line per partition, with fields separated by colons (':'). Lines beginning with a hash mark ('#') are considered comments and ignored (the entire "default" config file is commented out). Values are all case sensitive. The fields for each partition
    1. Mount point/usage indicator: This field indicated what the partition/slice should be used for. Allowed values are
      • ROOT for the root file system (required)
      • USR for the /usr file system (recommended, if missing becomes part of ROOT).
      • SWAP the swap partition (required)
      • VAR the /var file system (recommended, if missing becomes part of ROOT).
      • TMP the /tmp file system (recommended, if missing becomes part of ROOT).
      • CACHE the AFS cache partition, /usr/vice/cache file system (required) (I believe AFS client only supports this for ext2 or ext3 filesystem types).
      • BOOT the /boot file system (if missing becomes part of ROOT). Not fully supported?
      • GRUB this actually does not represent a partition, but indicates where GRUB should be installed. Defaults to the MBR of the disk ROOT is on.
    2. Disk partition device: The name of the disk partition being referred to. Use standard linux device names, e. g. hda1, sda7. The /dev directory prefix is assumed, and must not be included. Be sure to change the default hda to sda if using SCSI, etc.
    3. File system type: The type of file system to be on that partition. Any valid file system type accepted by mount and mkfs is legal. This field must not be provided for usage types SWAP or GRUB. It is optional in other cases, defaulting to ext3.
    4. Format flag: This flag should be either 1 or 0, indicating that the script should or should not, respectively, (mkfs) the partition first. If 0, it is assumed the partition has already had a valid filesystem of the specified type (see previous field) installed on it. Otherwise, the script will mkfs to the filesystem type specified in the previous field. Default is 1 ( it). This field must be left blank for usage types SWAP or GRUB.
    5. Mount flag: This flag should be either 1 or 0, indicating that the script should or should not, respectively, mount the filesystem named at the appropriate temporary mount point (root of the to be installed system will be temporarily mounted under /tmp/mnt, the others should be mounted in the appropriate subdirectory of the root filesystem of the to be installed system). If 0, it is assumed you already mounted it. Otherwise, the script will mount the filesystem in the appropriate directory (based on usage flag) with the appropriate file system type. Default is 1. This field must be left blank for usage types SWAP or GRUB.

    As can be seen, the first two fields are always required, and the remaining fields can be dropped off from the right (e.g. if only four fields are given, the last field (mount flag) is defaulted). Usage types SWAP and GRUB, since they do not represent file systems, may only have the first two fields set.

    Note that there is no sizing information; the partition sizes are set in the partition table with fdisk, etc. This file only says which partition is intended to be what. Any partitions that are irrelevant to the install of the new system (i. e. are purely for local data, or for other operating systems) should simply be omitted. It may be useful to keep this file on a floppy for use in future systems; particularly if calling glueinstall from a floppy.

    Typically, I find I generally only need to uncomment the "default" config lines, change hda to sda if using a SCSI or pseudo-SCSI device, and change the partition numbers.

    Example 1 This example gives the standard partitioning for a glued linux install onto the first IDE/ATA hard drive. (Of course, it really is foolish to use the advanced mode functionality for such a case). Note that /, /usr, /var, and /usr/vice/cache all are set to use the ext3 filesystem, and for the script to and mount due to the defaulting of some fields. /tmp and /boot are not listed, and so will be kept as part of the root filesystem rather than separate mount points. 

    ROOT:hda1:ext3:1:1
SWAP:hda2
USR:hda5:ext3
VAR:hda6
CACHE:hda7:ext3:1

    Example 2 This example gives a sample partitioning we use on some of our servers. The server originally had a special utility partition on sda1 and the original vendor operating system on sda2 which we did not wish to disturb in case we needed to contact the vendor on hardware issues (they often insist on testing the problem in the OS they listed the machine as being sold with). So instead we put all the linux stuff on logical partitions of the first SCSI drive. 

    ROOT:sda5:ext3:1:1
SWAP:sda6
USR:sda7:ext3:1:1
VAR:sda8:ext3:1:1
TMP:sda9:ext3:1:1
CACHE:sda10:ext3:1:1
    Note that we add a separate codeit(/tmp) filesystem, but leave /boot on the root filesystem. Grub will be installed on the master boot record of sda.
  4. Miscelleneous final steps: There are some final configuration steps needed. These may hopefully go away in a later version. Most involve correcting some entries in /boot/grub/grub.conf. The standard glue install will give you a chance to edit this, you should probably always say yes and check that the default is correct.

    If you have a separate boot partition, the /boot prefix should be removed from all the paths pointing to kernels and initrd images.

    If your /boot partition (or your / partition if /boot is not a separate filesystem) is not the first partition/slice of the disk grub is on, you will need to change all the occurences of hd0,0 to hd0,n where n is one less than the partition number of the /boot or / filesystem. E. g. for example 2 above, these should be changed to hd0,4

    There may be other changes needed in grub.conf for more complicated situations. If there is a problem booting, netboot again into maintenance mode, mount / and /boot if necessary and make the changes needed.

Appendix: Undocumented glueinstall arguments

Just for future reference, we are providing a list of undocumented arguments for the glueinstall (but if we document them here, they're no longer undocumented :) (Note: This section has not been updated in some time)

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