partman-auto recipe files Contents: 0. Introduction 1. Format of the recipes 2. Examples 3. LVM specific options 4. Architecture specific recipes 5. Limitations 6. How the actual partition sizes are computed 7. Appendix 0. INTRODUCTION --------------- partman-auto is the part of the partitioner that automatically partitions disks. It is controlled by recipes, which are provided in partman-auto as files, but may also be provided by other udebs, or by preseeding. This document explains the format of the recipes and how to use them. 1. FORMAT OF THE RECIPES ------------------------ All new lines and tabs in the recipe are converted to spaces. Then two or more consecutive spaces are converted to one space. Almost all tokens must be separated by spaces. An important exception is the opening curly bracket ("{"); before it there must be _no_ space. In the following rules we denote spaces by "_". ::=
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::=| ::=_: can be for example "Multi user system". ::=_:: The purpose of is to allow translation of the names of the recipes into different languages. ::=|_ ::=__. ::=___ is the minimal allowed size of the partition in megabytes. It is rounded to cylinder size, so if you make to be 20 MB and the cylinder size is 12MB, then it is possible for the partition to be only 12MB. These sizes may also be given as a percentage, which makes the size be that percentage of the system's total RAM, or (as of partman-auto 87) as a number plus a percentage (e.g. "2000+50%"), which makes the size be that number plus that percentage of the system's total RAM. is some size usually between and . It determines the priority of this partition in the contest with the other partitions for size. Notice that if is too small (relative to the priority of the other partitions) then this partition will have size close to . That's why it is recommended to give small partitions a larger than their . is the maximal size for the partition, i.e. a limit size such that there is no sense to make this partition larger. The special value "-1" is used to indicate unlimited partition size. is the file system as known to parted of this partition. It may be $default_filesystem to use partman's default (currently ext3). ::=|_ ::=|| ::=$primary{_}|$bootable{_}|$default_filesystem{_} $primary{_} says that the partition should be primary (if possible). $bootable{_} says that the bootable flag will be set. $default_filesystem{_} says that partman's default filesystem (currently ext3) should be used. ::={ } is a file to be created in the directory of the partition in partman's filesystem info. (See section 2.4 of the partman manual for details.) is the information to write in this file. ::=$lvmok{_}|$defaultignore{_}|$lvmignore{_} $lvmok{_} Indicates that the partition is permitted to be an LVM logical volume should an LVM partitioning scheme be in use. $defaultignore{_} Used to void a partition definition so that it is ignored in the default case. That is to say it will be valid in the LVM case. $lvmignore{_} Used to void a partition definition so that it is ignored in the LVM case. That is to say it will be valid in the default case. The specifiers defaultignore and lvmignore allow one recipe to define different handling of say the /boot partition between an LVM partitioning scheme and a non-LVM scheme. 2. EXAMPLES ----------- Here is a very simple recipe that creates a swap partition and uses the rest of the disk for one large root filesystem. partman-auto/text/atomic_scheme :: 500 10000 1000000 ext3 $primary{ } $bootable{ } method{ format } format{ } use_filesystem{ } filesystem{ ext3 } mountpoint{ / } . 64 512 300% linux-swap method{ swap } format{ } . Here the root partition must be at least 500 mb, and has effectively no maximum size. The swap partition ranges from 64 mb to 3 times the system's ram. Note the use of $bootable{ } to make the partition bootable, and $primary{ } to mark it as the primary partition. The specifiers used in this example are: method{ format } Used to make the partition be formatted. For swap partitions, change it to "swap". To create a new partition but do not format it, change "format" to "keep" (such a partition can be used to reserve for future use some disk space). format{ } Also needed to make the partition be formatted. use_filesystem{ } Specifies that the partition has a filesystem on it. filesystem{ ext3 } Specifies the filesystem to put on the partition. mountpoint{ / } Where to mount the partition. It is also possible to specify mount options. For example, to specify "nodev,ro" for a partition, add the following lines for that partition: options/nodev{ nodev } options/ro{ ro } It is also possible to specify filesystem labels, for filesystems that support labels (e.g. ext2, ext3). For example, to specify a label of "fred" for a partition, add the following line for that partition: label{ fred } Note that the partition must be one that will be reformatted during the installation, i.e. one for which you have specified method{ format } Here is another example; this time there is a smaller root partition, and a separate /home partition. partman-auto/text/home_scheme :: 300 4000 7000 ext3 $primary{ } $bootable{ } method{ format } format{ } use_filesystem{ } filesystem{ ext3 } mountpoint{ / } . 64 512 300% linux-swap method{ swap } format{ } . 100 10000 1000000000 ext3 method{ format } format{ } use_filesystem{ } filesystem{ ext3 } mountpoint{ /home } . Notice that the partitions will be created in the order they are defined in the recipe. 3. LVM SPECIFIC OPTIONS ----------------------- When using the "lvm" autopartioning method, specific options are recognized in the recipe. Those enable multiple disks to be partitioned at once, specifying partitions holding Physical Volumes, which Volume Group a Physical Volume holds, in which Volume Group a Logical Volume is put and the name of the Logical Volumes. Multiple disks can also be partitioned at the same time. Those must be specified in partman-auto/disk. Partitions that are neither on a Logical Volume, nor have a specific device specified (e.g. /boot) will default on being on the first disk. To explicitly declare a Physical Volume, define a partition as follows: 100 1000 1000000000 ext3 $defaultignore{ } $primary{ } method{ lvm } device{ /dev/hdb } vg_name{ vg00 } . Both "device{ ... }" and "vg_name{ }" are optional. The device *must* be listed in partman-auto/disk. The Volume Group holding a Logical Volume can be specified using "in_vg{ }", e.g.: 96 512 300% linux-swap $lvmok{ } in_vg{ vg00 } lv_name{ myswap } method{ swap } format{ } . "lv_name{ }" specifies the name of the Logical Volume being created. 4. ARCHITECTURE DEPENDENT RECIPES --------------------------------- Some architectures have specific requirements for their partitions. For example many of them require special partitions to support bootloading. For example, newworld powerpc machines need a newworld boot partition at the start of the disk. Here is an example fragment of a recipe file to create one; it should come before other partitions in a recipe. Notice that the partition is not formatted. 1 1 1 hfs $bootable{ } method{ newworld } . Another example is a netwinder, which requires a small /boot partition formated in revision 0 ext2. 50 500 100 ext2 $primary{ } $bootable{ } method{ format } format{ } use_filesystem{ } filesystem{ ext2r0 } mountpoint{ /boot } . And finally, an example of how to set up the efi boot partition needed on ia64. 100 100 150 fat16 $primary{ } method{ efi } format{ } . For other examples, see the architecture-specific recipes in partman-auto. 5. LIMITATIONS -------------- Due to limitation of the algorithms in partman-auto, there must be at least one partition with high maximal size so that the whole free space can be used. Usually you can give the partition containing /home a maximal size 1000000000 which is high enough for the present storage devices. If the large /home is not an option for you, you can also define in the recipe one additional partition with size 1000000000, method "keep" and leave it unmounted. When the installation completes you can remove it. Do not use higher than 1000000000 numbers because the shell arithmetic is limited to 31 bits (on i386). 6. HOW THE ACTUAL PARTITION SIZES ARE COMPUTED ---------------------------------------------- Suppose we have to create N partitions and min[i], max[i] and priority[i] are the minimal size, the maximal size and the priority of the partition #i as described in section 1. Let free_space be the size of the free space to partition. Then do the following: for(i=1;i<=N;i++) { factor[i] = priority[i] - min[i]; } ready = FALSE; while (! ready) { minsum = min[1] + min[2] + ... + min[N]; factsum = factor[1] + factor[2] + ... + factor[N]; ready = TRUE; for(i=1;i<=N;i++) { x = min[i] + (free_space - minsum) * factor[i] / factsum; if (x > max[i]) x = max[i]; if (x != min[i]) { ready = FALSE; min[i] = x; } } } Then min[i] will be the size of partition #i. 7. APPENDIX ----------- On May 25th 2004, it was noted that on i386 systems, the very minimum size of a Debian installation on a classical (/, /usr, /usr, /home) setup was: 48MB on / (6MB on /boot) 77MB on /usr 17MB on /var It is thus wise to use minimum values with this consideration in mind. #261244: 70MB are required for /var #265290: 1.8GB are not enough for / with desktop