Source string Read only

(itstool) path: row/entry
39/390
Context English State
/
|
+--- A1
| |
| +--- C1
| |
| `--- C2
|
`--- A2
|
+--- B1
|
`--- B2
It is entirely possible to have one large root file system, and not need to create any others. There are some drawbacks to this approach, and one advantage.
Benefits of Multiple File Systems
Different file systems can have different <firstterm>mount options</firstterm>. For example, the root file system can be mounted read-only, making it impossible for users to inadvertently delete or edit a critical file. Separating user-writable file systems, such as <filename>/home</filename>, from other file systems allows them to be mounted <firstterm>nosuid</firstterm>. This option prevents the <firstterm>suid</firstterm>/<firstterm>guid</firstterm> bits on executables stored on the file system from taking effect, possibly improving security.
FreeBSD automatically optimizes the layout of files on a file system, depending on how the file system is being used. So a file system that contains many small files that are written frequently will have a different optimization to one that contains fewer, larger files. By having one big file system this optimization breaks down.
FreeBSD's file systems are robust if power is lost. However, a power loss at a critical point could still damage the structure of the file system. By splitting data over multiple file systems it is more likely that the system will still come up, making it easier to restore from backup as necessary.
Benefit of a Single File System
File systems are a fixed size. If you create a file system when you install FreeBSD and give it a specific size, you may later discover that you need to make the partition bigger. This is not easily accomplished without backing up, recreating the file system with the new size, and then restoring the backed up data.
FreeBSD features the <citerefentry><refentrytitle>growfs</refentrytitle><manvolnum>8</manvolnum></citerefentry> command, which makes it possible to increase the size of file system on the fly, removing this limitation.
File systems are contained in partitions. This does not have the same meaning as the common usage of the term partition (for example, <trademark class="registered">MS-DOS</trademark> partition), because of FreeBSD's <trademark class="registered">UNIX</trademark> heritage. Each partition is identified by a letter from <literal>a</literal> through to <literal>h</literal>. Each partition can contain only one file system, which means that file systems are often described by either their typical mount point in the file system hierarchy, or the letter of the partition they are contained in.
FreeBSD also uses disk space for <firstterm>swap space</firstterm> to provide <firstterm>virtual memory</firstterm>. This allows your computer to behave as though it has much more memory than it actually does. When FreeBSD runs out of memory, it moves some of the data that is not currently being used to the swap space, and moves it back in (moving something else out) when it needs it.
Some partitions have certain conventions associated with them.
Partition
Convention
<literal>a</literal>
Normally contains the root file system.
<literal>b</literal>
Normally contains swap space.
<literal>c</literal>
Normally the same size as the enclosing slice. This allows utilities that need to work on the entire slice, such as a bad block scanner, to work on the <literal>c</literal> partition. A file system would not normally be created on this partition.
<literal>d</literal>
Partition <literal>d</literal> used to have a special meaning associated with it, although that is now gone and <literal>d</literal> may work as any normal partition.
Disks in FreeBSD are divided into slices, referred to in <trademark class="registered">Windows</trademark> as partitions, which are numbered from 1 to 4. These are then divided into partitions, which contain file systems, and are labeled using letters.
<primary>slices</primary>
<primary>partitions</primary>
<primary>dangerously dedicated</primary>
Slice numbers follow the device name, prefixed with an <literal>s</literal>, starting at 1. So <quote>da0<emphasis>s1</emphasis></quote> is the first slice on the first SCSI drive. There can only be four physical slices on a disk, but there can be logical slices inside physical slices of the appropriate type. These extended slices are numbered starting at 5, so <quote>ada0<emphasis>s5</emphasis></quote> is the first extended slice on the first SATA disk. These devices are used by file systems that expect to occupy a slice.
Slices, <quote>dangerously dedicated</quote> physical drives, and other drives contain <firstterm>partitions</firstterm>, which are represented as letters from <literal>a</literal> to <literal>h</literal>. This letter is appended to the device name, so <quote>da0<emphasis>a</emphasis></quote> is the <literal>a</literal> partition on the first <literal>da</literal> drive, which is <quote>dangerously dedicated</quote>. <quote>ada1s3<emphasis>e</emphasis></quote> is the fifth partition in the third slice of the second SATA disk drive.
Finally, each disk on the system is identified. A disk name starts with a code that indicates the type of disk, and then a number, indicating which disk it is. Unlike slices, disk numbering starts at 0. Common codes are listed in <xref linkend="disks-naming"/>.
When referring to a partition, include the disk name, <literal>s</literal>, the slice number, and then the partition letter. Examples are shown in <xref linkend="basics-disk-slice-part"/>.
<xref linkend="basics-concept-disk-model"/> shows a conceptual model of a disk layout.

Loading…

No matching activity found.

Browse all component changes

Glossary

English English
No related strings found in the glossary.

Source information

Source string comment
(itstool) path: row/entry
Flags
read-only
Source string location
book.translate.xml:7868
String age
a year ago
Source string age
a year ago
Translation file
books/handbook.pot, string 1265