Handbook:IA64/Blocks/Disks/ja

Partitions
Although it is theoretically possible to use a full disk to house your Linux system, this is almost never done in practice. Instead, full disk block devices are split up in smaller, more manageable block devices. On IA64 systems, these are called partitions.

Itanium systems use EFI, the Extensible Firmware Interface, for booting. The partition table format that EFI understands is called GPT, or GUID Partition Table. The partitioning program that understands GPT is called "parted", so that is the tool used below. Additionally, EFI can only read FAT filesystems, so that is the format to use for the EFI boot partition, where the kernel will be installed by "elilo".

Advanced storage
The IA64 Installation CDs provide support for LVM2. LVM2 increases the flexibility offered by the partitioning setup. During the installation instructions, we will focus on "regular" partitions, but it is still good to know LVM2 is supported as well.

Non-default example partition scheme
An example partitioning for a 20GB disk is shown below, used as a demonstration laptop (containing webserver, mailserver, gnome, ...):

is rather full (83% used) here, but once all software is installed, doesn't tend to grow that much. Although allocating a few gigabytes of disk space for may seem excessive, remember that portage uses this partition by default for compiling packages. To keep at a more reasonable size, such as 1GB, alter the PORTAGE_TMPDIR variable in  to point to the partition with enough free space for compiling extremely large packages such as LibreOffice.

Using parted to partition the disk
The following parts explain how to create the example partition layout used in the remainder of the installation instructions, namely:

Change the partition layout according to personal preference.

Viewing the current partition layout
parted is the GNU partition editor. Fire up parted on the disk (in our example, we use ):

Once in parted, a prompt that looks like this shows up:

At this point one of the available commands is help, to see the other available commands. Another command is print to display the disk's current partition configuration:

This particular configuration is very similar to the one recommended above. Note on the second line that the partition table is type is GPT. If it is different, then the ia64 system will not be able to boot from this disk. To explain how partitions are created, let's first remove the partitions and recreate them.

Removing all partitions
The easy way to remove all partitions and start fresh, which guarantees that we are using the correct partition type, is to make a new partition table using the mklabel command. This results in an empty GPT partition table.

Now that the partition table is empty, we're ready to create the partitions. We will use a default partitioning scheme as discussed previously. Of course, don't follow these instructions to the letter but adjust to personal preference.

Creating the EFI boot partition
First create a small EFI boot partition. This is required to be a FAT filesystem in order for the IA64 firmware to read it. Our example makes this 32 MB, which is appropriate for storing kernels and elilo configuration. Expect each IA64 kernel to be around 5 MB, so this configuration leaves some room to grow and experiment.

Creating the swap partition
Let's now create the swap partition. The classic size to make the swap partition was twice the amount of RAM in the system. In modern systems with lots of RAM, this is no longer necessary. For most desktop systems, a 512 megabyte swap partition is sufficient. For a server, consider something larger to reflect the anticipated needs of the server.

Creating the root partition
Finally, create the root partition. Our configuration will make the root partition to occupy the rest of the disk. We default to ext4, but it is possible to use ext2, jfs, reiserfs or xfs. The actual filesystem is not created in this step, but the partition table contains an indication of what kind of filesystem is stored on each partition, and it's a good idea to make the table match the intentions.

Exiting parted
To quit from parted, type quit. There's no need to take a separate step to save the partition layout since parted has been saving it all along. Parted will give a reminder to update the file, which is done later in the installation instructions.