DICE Disk Partitioning on SL5 and FC6

Here's how the default disk partitioning is decided for DICE machines. Note that this is a snapshot of how things worked in February 2008; things may have changed by the time you read this, and for the canonical information you should refer to the header files in subversion.

Desktop machines

Office machines and student lab machines come into this category.

Summary

25GB root partition / hda1 or sda1
2GB swap partition hda2 or sda2
2GB AFS cache partition /var/cache/afs hda3 or sda3
remaining free space scratch partition /disk/scratch hda4 or sda4

The scratch partition is writeable by normal users on office machines, but not on student lab machines.

Variables you can use

FIRST_INSTALL
If this is defined in a machine's LCFG file, above where the headers are included, then running the DICE install process will repartition the disk without saving anything on it. If it's not defined there then the DICE install process won't partition the disk and will preserve the contents of the local data partition (generally called /disk/scratch).

More detail

Office machines are expected to include one of the dice/options/office-site.h headers. These all include dice/options/office.h which includes dice/options/desktop.h and dice/options/scratch-disk.h.

Student lab machines are expected to include one of the dice/options/studentlabs-site.h headers. These all include dice/options/studentlabs.h which includes dice/options/desktop.h.

dice/options/desktop.h defines the name of the scratch partition (in DICE_LOCAL_PART) then includes dice/options/disk-layout.h.

dice/options/disk-layout.h contains all the rest of the disk partitioning configuration, except for adjusting the permissions of the scratch partition. For office machines this is done in dice/options/scratch-disk.h and for student lab machines it's done in dice/options/studentlabs.h.

SCSI

The default disk name is hda. Machines with SCSI disks instead of IDE will instead have sda. The change from hda to sda is done by including lcfg/options/scsiroot.h. This is included at the end of the hardware model headers in lcfg/hw/ which are included by the dice/hw/ hardware model headers which are included in machines' own LCFG files - so lcfg/options/scsiroot.h should not normally need to be included in the LCFG file. The settings in lcfg/options/scsiroot.h are largely overridden by those in dice/options/disk-layout.h - however the latter chooses disk partition names based on whether or not lcfg/options/scsiroot.h has been included.

Non-desktops

To be written...

Summary

To be written...

Variables you can use

_NO_DEFAULT_LOCALPART
This variable is defined for all DICE machines.

More detail

Servers are expected to include dice/options/server.h instead of dice/options/desktop.h. In contrast to the latter, dice/options/server.h does not impose any DICE partitioning scheme. Servers therefore largely use the LCFG-level disk partitioning default settings.

Most of the disk partition configuration resources are in lcfg/defaults/fstab.h. This is included via the dice/os/ header in the machine's own LCFG file. (The dice/os/ file includes dice/defaults.h which includes ed/defaults.h which includes lcfg/defaults.h which includes lcfg/defaults/fstab.h.)

-- ChrisCooke - 18 Feb 2008

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Topic revision: r1 - 18 Feb 2008 - 13:52:10 - ChrisCooke
 
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