136 lines
6.4 KiB
Plaintext
136 lines
6.4 KiB
Plaintext
This is the FreeBSD DiskLabel Editor.
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NOTE: If you're entering this editor from the update procedure then
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you probably shouldn't (C)reate anything at all but rather use only
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the (M)ount command to check and mount existing partitions for
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upgrading.
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If you would like the label editor to do most of the following for
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you, simply type `A' for automatic partitioning of the disk.
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If you wish to create partitions manually you may do so by moving the
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highlighted selection bar with the arrow keys over the FreeBSD
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partition(s) displayed at the top of the screen. Typing (C)reate
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while a partition with available free space is selected will allow you
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to create a BSD partition inside of it using some or all of its
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available space.
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Typing (M)ount over an existing partition entry (displayed in the
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middle of the screen) will allow you to set a mount point for it
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without initializing it. If you want it initialized, use the (T)oggle
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command to flip the Newfs flag. When Newfs is set to "Y", the
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filesystem in question will be ERASED and rebuilt from scratch!
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You should use this editor to create at least the following
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filesystems:
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Name Purpose Min Size? Optional?
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---- ------- --------- ---------
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/ Root filesystem 20MB No
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swap Swap space 2 * MEM No
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/usr System & user files 80MB or more Yes
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Note: If you do not create a /usr filesystem then your / filesystem
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will need to be bigger - at least 100MB. This is not recommended as
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any media errors that may occur during disk I/O to user files will
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corrupt the filesystem containing vital system files as well. It is
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for this reason that / is generally kept on its own filesystem, where
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it should be considered essentially "read only" in your administration
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of it.
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Swap space is a little tricker, and the rule of "2 * MEM" is simply a
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best-guess approximation and not necessarily accurate for your
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intended usage of the system. If you intend to use the system heavily
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in a server or multi-user application, you may be well advised to
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increase this size. You may also create swap space on multiple drives
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for a larger "total" swap and this is, in fact, recommended if you
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have multiple, fast drives for which such load-balancing can only help
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overall I/O performance.
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The /usr filesystem should be sized according to what kind of
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distributions you're trying to load and how many packages you intend
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to install in locations like /usr/local. You can also make /usr/local
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a separate filesystem if you don't want to risk filling up your /usr
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by mistake.
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Another useful filesystem to create is /var, which contains mail, news
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printer spool files and other temporary items. It is a popular
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candidate for a separate partition and should be sized according to
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your estimates of the amount of mail, news or spooled print jobs that
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may be stored there.
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WARNING: If you do not create a separate filesystem for /var, space
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for such files will be allocated out of the root (/) filesystem
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instead. You may therefore wish to make the / partition bigger if you
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expect a lot of mail or news and do not want to make /var its own
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partition.
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If you're new to this installation, you might also want to read the
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following explanation of how FreeBSD's new "slice" paradigm for
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looking at disk storage works:
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In FreeBSD's new system, a device name can be broken up into up to 3
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parts. Take a typical name like ``/dev/da0s1a'':
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The first three characters represent the drive name. If we had
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a system with two SCSI drives on it then we'd see /dev/da0 and
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/dev/da1 as the device entries representing the entire drives.
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Next you have the "slice" (or "FDISK Partition") number,
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as seen in the Partition Editor. Assuming that our da0
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contained two slices, a FreeBSD slice and a DOS slice, that
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would give us /dev/da0s1 and /dev/da0s2 as device entries pointing
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to the entire slices.
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Next, if a slice is a FreeBSD slice, you can have a number of
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(confusingly named) "partitions" inside of it.
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These partitions are where various filesystems or swap areas live,
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and using our hypothetical two-SCSI-disk machine again, we might
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have something like the following layout on da0:
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Name Mountpoint
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---- ----------
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da0s1a /
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da0s1b <swap space>
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da0s1e /usr
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Once you understand all this, then the purpose of the label editor
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becomes fairly clear: You're carving up the FreeBSD slices displayed
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at the top of the screen into smaller pieces, which are displayed in
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the middle of the screen, and then assigning FreeBSD file system names
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(mount points) to them.
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You can also use the label editor to mount existing partitions/slices
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into your filesystem hierarchy, as is frequently done for DOS FAT
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slices. For FreeBSD partitions, you can also toggle the "newfs" state
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so that the partitions are either (re)created from scratch or simply
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checked and mounted (the contents are preserved).
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If you set (S)oftUpdates on a filesystem, it will cause the
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"Soft Updates" policy to be in effect for it. This basically causes
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both metadata and data blocks to be written asynchronously to disk,
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but with extra state information which causes the metadata and any
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related data blocks to be committed in a single transaction. This
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results in async metadata update speeds (which are considerably
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faster than the default sync) without the potential for data loss
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which could occur if you simply mounted the filesystem with purely
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"async" update policy and then had a power failure. If you wish
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to later turn the softupdates policy back off, use the command
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"tunefs -n disable devicename". NOTE: It is probably not wise
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to use this on your root filesystem unless you have a large
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(e.g. non-standard size) root. The reason is that smaller filesystems
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with significant activity can temporarily overflow if the soft updates
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policy results in free'd blocks not being "garbage collected" as fast
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as they're being requested.
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When you're done, type `Q' to exit.
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No actual changes will be made to the disk until you (C)ommit from the
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Install menu or (W)rite directly from this one. You're working with
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what is essentially a copy of the disk label(s), both here and in the
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FDISK Partition Editor, and the actual on-disk labels won't be
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affected by any changes you make until you explicitly say so.
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