Change Partition Size On OSRCD

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Note: This process to be amended to show how to add partitions, not just change the size of the existing partitions.

The Partition_Table referred to is in


For example, on a RaQ 4r, it's


The relevant bit of the release_spec file looks like:

# This is the partition table for the product
%begin Partition_Table
%end Partition_Table

The format of each line in this section is:

Start, Size, ID

The sfdisk command used in the cobalt_install script, found in



/sbin/sfdisk -f -L -uM

so we're working in megabytes (that's what the -uM switch is for)

  • Start = MB to start at (first available MB if left blank)
  • Size = number of MB (all if left blank)
  • ID = type of partition (Linux, Swap, MSDOS, or other)

First, let's look at a working system (my own RaQ 4r). Run

sfdisk -uM -l /dev/hda

to get something like:

Disk /dev/hda: 58168 cylinders, 16 heads, 63 sectors/track
Units = megabytes of 1048576 bytes, blocks of 1024 bytes, counting from 0

   Device Boot Start   End     MB   #blocks   Id  System
/dev/hda1         0+   750-   751-   768095+  fd  Linux raid autodetect
/dev/hda2       750+   908-   159-   162288    5  Extended
/dev/hda3       908+  1108-   201-   205128   fd  Linux raid autodetect
/dev/hda4      1108+ 28629- 27521- 28181160   fd  Linux raid autodetect
/dev/hda5       750+   780-    31-    30743+  83  Linux
/dev/hda6       780+   908-   129-   131543+  fd  Linux raid autodetect

(+ and - after some numbers mean rounding has taken place)

So the Partition_Table info on the OSRCD says:

1st partition (/dev/hda1) = 750 MB, type 83
Regular Linux partition (/)

2nd partition (/dev/hda2) = 158 MB, type 5
Extended partition (holds /dev/hda5 and /dev/hda6)

3rd partition (/dev/hda3) = 200 MB, type 83
Regular Linux partition (/var)

4th partition (/dev/hda4) = rest of disk, type 83
Regular Linux partition (/home)

5th partition (/dev/hda5) = 30 MB, type 83

6th partition (/dev/hda6) = rest of "disk", type 83
(should be about 158-30 or 128MB)

/dev/hda5 and /dev/hda6 are in the Extended partition (to be honest, I'm not sure of their use - fdisk doesn't see them, so I don't think they are actually used... probably a remnant from some early disk layout that never got removed...)

So to give yourself a 1 GB /var and 2 GB / (and the rest in /home), you'd make your Partition_Table section look like

# This is the partition table for the product
%begin Partition_Table
%end Partition_Table

(actual sizes of / and /var might vary a couple of MB depending on rounding, etc.)

Then burn your new CD, and your RaQ now has bigger / and /var partition!

NOTE: UNOFFICIAL AND UNSUPPORTED. USE AT YOUR OWN RISK. (Worst case, though, is you have to rebuild the disk again with a "real" OSRCD...)

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