vinum(4)

NAME
vinum - Logical Volume Manager

SYNOPSIS
modload /lkm/vinum.o
modload /lkm/Vinum.o

DESCRIPTION
vinum is a logical volume manager. It provides the following features:

•   It provides device-independent logical disks, called volumes. Volumes are not restricted to the size of any disk on the system.

•   The volumes consist of one or more plexes, each of which contain the entire address space of a volume. This represents an implementation of RAID-1 (mirroring). Multiple plexes can also be used for

    •   Increased read throughput. vinum will read data from the least active disk, so if a volume has plexes on multiple disks, more data can be read in parallel. vinum reads data from only one plex, but it writes data to all plexes.

    •   Increased reliability. By storing plexes on different disks, data will remain available even if one of the plexes becomes unavailable. In comparison with a RAID-5 plex (see below), using multiple plexes requires more storage space, but gives better performance, particularly in the case of a drive failure.

    •   Additional plexes can be used for on-line data reorganization. By attaching an additional plex and subsequently detaching one of the older plexes, data can be moved on-line without compromising access.

    •   An additional plex can be used to obtain a consistent dump of a file system. By attaching an additional plex and detaching at a specific time, the detached plex becomes an accurate snapshot of the file system at the time of detachment.

•   Each plex consists of one or more logical disk slices, called subdisks. Subdisks are defined as a contiguous block of physical disk storage. A plex may consist of any reasonable number of subdisks (in other words, the real limit is not the number, but other factors, such as memory and performance, associated with maintaining a large number of subdisks).

•   A number of mappings between subdisks and plexes are available:

    •   Concatenated plexes consist of one or more subdisks, each of which is mapped to a contiguous part of the plex address space.

    •   Striped plexes consist of two or more subdisks of equal size. The file address space is mapped in stripes, integral fractions of the subdisk size. Consecutive plex address space is mapped to stripes in each subdisk in turn. The subdisks of a striped plex must all be the same size.

    •   RAID-5 plexes require at least three equal-sized subdisks. They resemble striped plexes, except that in each stripe, one subdisk stores parity information. This subdisk changes in each stripe: in the first stripe, it is the first subdisk, in the second it is the second subdisk, etc. In the event of a single disk failure, vinum will recover the data based on the information stored on the remaining subdisks. This mapping is particularly suited to read-intensive access. The subdisks of a RAID-5 plex must all be the same size.

•   Drives are the lowest level of the storage hierarchy. They represent disk special devices.

•   vinum offers automatic startup. Unlike UNIX file systems, vinum volumes contain all the configuration information needed to ensure that they are started correctly when the subsystem is enabled. This is also a significant advantage over the Veritas™ File System. This feature regards the presence of the volumes. It does not mean that the volumes will be mounted automatically, since the standard startup procedures with /etc/fstab perform this function.

KERNEL CONFIGURATION
vinum is currently supplied as a loadable kernel module (LKM), and does not require configuration. As with other LKMs, it is absolutely necessary to match the LKM to the version of the operating system.

vinum is currently available in two versions: a freely available version which does not contain RAID-5 functionality, and a full version including RAID-5 functionality, which is available from Cybernet Systems Inc. (http://www.cybernet.com).

RUNNING VINUM
The freely available version of the vinum LKM is called /lkm/vinum.o, and the RAID-5 version is /lkm/Vinum.o. To load the module:

    # modload /lkm/vinum.o

After loading vinum, it must be confiugred. In an existing installation, the following command reads the configuration an existing set of disks:

    # vinum read /dev/da1h /dev/da2h /dev/da3h /dev/da4h /dev/da5h /dev/da6h

This command must specify all of the devices used by vinum. vinum(8) reads the configuration from the device with the newest configuration file, then updates it if necessary with additional information from successively older configurations. These commands are normally embedded in the startup file /etc/rc.local.

See vinum(8) for information on how to create a vinum configuration.

  CONFIGURING AND STARTING OBJECTS
Use the vinum(8) utility to configure and start vinum objects.

IOCTL CALLS
ioctl calls are intended for the use of the vinum configuration program only. The are described in the header file /sys/sys/vinumio.h

DISK LABELS
Conventional disk special devices have a disk label in the second sector of the device. See disklabel(5) for more details. This disk label describes the layout of the partitions within the device. vinum does not subdivide volumes, so volumes do not contain a physical disk label. For convenience, vinum implements the ioctl calls DIOCGDINFO (get disk label), DIOCGPART (get partition information), DIOCWDINFO (write partition information) and DIOCSDINFO (set partition information). DIOCGDINFO and DIOCGPART refer to an internal representation of the disk label which is not present on the volume. As a result, the -r option of disklabel(8), which reads the ``raw disk'', will fail.

In general, disklabel(8) serves no useful purpose on a vinum volume. If you run it, it will show you three partitions, a, b and c, all the same except for the fstype, for example:

    3 partitions:
    #        size   offset    fstype   [fsize bsize bps/cpg]
      a:     2048        0    4.2BSD     1024  8192     0   # (Cyl.    0 - 0)
      b:     2048        0      swap                        # (Cyl.    0 - 0)
      c:     2048        0    unused        0     0         # (Cyl.    0 - 0)

vinum ignores the DIOCWDINFO and DIOCSDINFO ioctls, since there is nothing to change. As a result, any attempt to modify the disk label will be silently ignored.

MAKING FILE SYSTEMS
Since vinum volumes do not contain partitions, the names do not need to conform to the standard rules for naming disk partitions. For a physical disk partition, the last letter of the device name specifies the partition identifier (a to h). vinum volumes need not conform to this convention, but if they do not, newfs will complain that it cannot determine the partition. To solve this problem, use the -v flag to newfs.

OBJECT NAMING
vinum assigns default names to plexes and subdisks, although they may be overridden. We do not recommend overriding the default names. Experience with the Veritas(tm) volume manager, which allows arbitary naming of objects, has shown that this flexibility does not bring a significant advantage, and it can cause confusion.

Names may contain any non-blank character, but it is recommended to restrict them to letters, digits and the underscore characters. The names of volumes, plexes and subdisks may be up to 64 characters long, and the names of drives may up to 32 characters long. When choosing volume and plex names, bear in mind that automatically generated plex and subvolume names are longer than the name from which they are derived.

•   When vinum(8) creates or deletes objects, it creates a directory /dev/vinum, in which it makes device entries for each volume it finds. It also creates subdirectories, /dev/vinum/plex and /dev/vinum/sd, in which it stores device entries for the plexes and subdisks. In addition, it creates two more directories, /dev/vinum/vol and /dev/vinum/drive, in which it stores hierarchical information for volumes and drives.

•   Unlike UNIX drives, vinum volumes are not subdivided into partitions, and thus do not contain a disk label. Unfortunately, this confuses a number of utilities, notably newfs, which normally tries to interpret the last letter of a vinum volume name as a partition identifier. If you use a volume name which does not end in the letters a to c, you must use the -v flag to newfs in order to tell it to ignore this convention.

•   Plexes do not need to be assigned explicit names. By default, a plex name is the name of the volume followed by the letters .p and the number of the plex. For example, the plexes of volume vol3 are called vol3.p0, vol3.p1 and so on. These names can be overridden, but it is not recommended.

•   Like plexes, subdisks are assigned names automatically, and explicit naming is discouraged. A subdisk name is the name of the plex followed by the letters .s and a number identifying the subdisk. For example, the subdisks of plex vol3.p0 are called vol3.p0.s0, vol3.p0.s1 and so on.

•   By contrast, drives must be named. This makes it possible to move a drive to a different location and still recognize it automatically. Drive names may be up to 32 characters long.

EXAMPLE

Assume the vinum objects described in the section CONFIGURATION FILE in vinum(8). The directory /dev/vinum looks like:

    # ls -lR /dev/vinum/ /dev/rvinum
    total 5
    brwxr-xr--  1 root  wheel   25,   2 Mar 30 16:08 concat
    brwx------  1 root  wheel   25, 0x40000000 Mar 30 16:08 control
    drwxrwxrwx  2 root  wheel       512 Mar 30 16:08 drive
    drwxrwxrwx  2 root  wheel       512 Mar 30 16:08 plex
    drwxrwxrwx  2 root  wheel       512 Mar 30 16:08 rvol
    drwxrwxrwx  2 root  wheel       512 Mar 30 16:08 sd
    brwxr-xr--  1 root  wheel   25,   3 Mar 30 16:08 strcon
    brwxr-xr--  1 root  wheel   25,   1 Mar 30 16:08 stripe
    brwxr-xr--  1 root  wheel   25,   0 Mar 30 16:08 tinyvol
    drwxrwxrwx  7 root  wheel       512 Mar 30 16:08 vol
    brwxr-xr--  1 root  wheel   25,   4 Mar 30 16:08 vol5
    /dev/vinum/drive:
    total 0
    brw-r-----  1 root  operator    4,  15 Oct 21 16:51 drive2
    brw-r-----  1 root  operator    4,  31 Oct 21 16:51 drive4
    /dev/vinum/plex:
    total 0
    brwxr-xr--  1 root  wheel   25, 0x10000002 Mar 30 16:08 concat.p0
    brwxr-xr--  1 root  wheel   25, 0x10010002 Mar 30 16:08 concat.p1
    brwxr-xr--  1 root  wheel   25, 0x10000003 Mar 30 16:08 strcon.p0
    brwxr-xr--  1 root  wheel   25, 0x10010003 Mar 30 16:08 strcon.p1
    brwxr-xr--  1 root  wheel   25, 0x10000001 Mar 30 16:08 stripe.p0
    brwxr-xr--  1 root  wheel   25, 0x10000000 Mar 30 16:08 tinyvol.p0
    brwxr-xr--  1 root  wheel   25, 0x10000004 Mar 30 16:08 vol5.p0
    brwxr-xr--  1 root  wheel   25, 0x10010004 Mar 30 16:08 vol5.p1
    /dev/vinum/rvol:
    total 0
    crwxr-xr--  1 root  wheel   91,   2 Mar 30 16:08 concat
    crwxr-xr--  1 root  wheel   91,   3 Mar 30 16:08 strcon
    crwxr-xr--  1 root  wheel   91,   1 Mar 30 16:08 stripe
    crwxr-xr--  1 root  wheel   91,   0 Mar 30 16:08 tinyvol
    crwxr-xr--  1 root  wheel   91,   4 Mar 30 16:08 vol5
    /dev/vinum/sd:
    total 0
    brwxr-xr--  1 root  wheel   25, 0x20000002 Mar 30 16:08 concat.p0.s0
    brwxr-xr--  1 root  wheel   25, 0x20100002 Mar 30 16:08 concat.p0.s1
    brwxr-xr--  1 root  wheel   25, 0x20010002 Mar 30 16:08 concat.p1.s0
    brwxr-xr--  1 root  wheel   25, 0x20000003 Mar 30 16:08 strcon.p0.s0
    brwxr-xr--  1 root  wheel   25, 0x20100003 Mar 30 16:08 strcon.p0.s1
    brwxr-xr--  1 root  wheel   25, 0x20010003 Mar 30 16:08 strcon.p1.s0
    brwxr-xr--  1 root  wheel   25, 0x20110003 Mar 30 16:08 strcon.p1.s1
    brwxr-xr--  1 root  wheel   25, 0x20000001 Mar 30 16:08 stripe.p0.s0
    brwxr-xr--  1 root  wheel   25, 0x20100001 Mar 30 16:08 stripe.p0.s1
    brwxr-xr--  1 root  wheel   25, 0x20000000 Mar 30 16:08 tinyvol.p0.s0
    brwxr-xr--  1 root  wheel   25, 0x20100000 Mar 30 16:08 tinyvol.p0.s1
    brwxr-xr--  1 root  wheel   25, 0x20000004 Mar 30 16:08 vol5.p0.s0
    brwxr-xr--  1 root  wheel   25, 0x20100004 Mar 30 16:08 vol5.p0.s1
    brwxr-xr--  1 root  wheel   25, 0x20010004 Mar 30 16:08 vol5.p1.s0
    brwxr-xr--  1 root  wheel   25, 0x20110004 Mar 30 16:08 vol5.p1.s1
    /dev/vinum/vol:
    total 5
    brwxr-xr--  1 root  wheel   25,   2 Mar 30 16:08 concat
    drwxr-xr-x  4 root  wheel       512 Mar 30 16:08 concat.plex
    brwxr-xr--  1 root  wheel   25,   3 Mar 30 16:08 strcon
    drwxr-xr-x  4 root  wheel       512 Mar 30 16:08 strcon.plex
    brwxr-xr--  1 root  wheel   25,   1 Mar 30 16:08 stripe
    drwxr-xr-x  3 root  wheel       512 Mar 30 16:08 stripe.plex
    brwxr-xr--  1 root  wheel   25,   0 Mar 30 16:08 tinyvol
    drwxr-xr-x  3 root  wheel       512 Mar 30 16:08 tinyvol.plex
    brwxr-xr--  1 root  wheel   25,   4 Mar 30 16:08 vol5
    drwxr-xr-x  4 root  wheel       512 Mar 30 16:08 vol5.plex
    /dev/vinum/vol/concat.plex:
    total 2
    brwxr-xr--  1 root  wheel   25, 0x10000002 Mar 30 16:08 concat.p0
    drwxr-xr-x  2 root  wheel       512 Mar 30 16:08 concat.p0.sd
    brwxr-xr--  1 root  wheel   25, 0x10010002 Mar 30 16:08 concat.p1
    drwxr-xr-x  2 root  wheel       512 Mar 30 16:08 concat.p1.sd
    /dev/vinum/vol/concat.plex/concat.p0.sd:
    total 0
    brwxr-xr--  1 root  wheel   25, 0x20000002 Mar 30 16:08 concat.p0.s0
    brwxr-xr--  1 root  wheel   25, 0x20100002 Mar 30 16:08 concat.p0.s1
    /dev/vinum/vol/concat.plex/concat.p1.sd:
    total 0
    brwxr-xr--  1 root  wheel   25, 0x20010002 Mar 30 16:08 concat.p1.s0
    /dev/vinum/vol/strcon.plex:
    total 2
    brwxr-xr--  1 root  wheel   25, 0x10000003 Mar 30 16:08 strcon.p0
    drwxr-xr-x  2 root  wheel       512 Mar 30 16:08 strcon.p0.sd
    brwxr-xr--  1 root  wheel   25, 0x10010003 Mar 30 16:08 strcon.p1
    drwxr-xr-x  2 root  wheel       512 Mar 30 16:08 strcon.p1.sd
    /dev/vinum/vol/strcon.plex/strcon.p0.sd:
    total 0
    brwxr-xr--  1 root  wheel   25, 0x20000003 Mar 30 16:08 strcon.p0.s0
    brwxr-xr--  1 root  wheel   25, 0x20100003 Mar 30 16:08 strcon.p0.s1
    /dev/vinum/vol/strcon.plex/strcon.p1.sd:
    total 0
    brwxr-xr--  1 root  wheel   25, 0x20010003 Mar 30 16:08 strcon.p1.s0
    brwxr-xr--  1 root  wheel   25, 0x20110003 Mar 30 16:08 strcon.p1.s1
    /dev/vinum/vol/stripe.plex:
    total 1
    brwxr-xr--  1 root  wheel   25, 0x10000001 Mar 30 16:08 stripe.p0
    drwxr-xr-x  2 root  wheel       512 Mar 30 16:08 stripe.p0.sd
    /dev/vinum/vol/stripe.plex/stripe.p0.sd:
    total 0
    brwxr-xr--  1 root  wheel   25, 0x20000001 Mar 30 16:08 stripe.p0.s0
    brwxr-xr--  1 root  wheel   25, 0x20100001 Mar 30 16:08 stripe.p0.s1
    /dev/vinum/vol/tinyvol.plex:
    total 1
    brwxr-xr--  1 root  wheel   25, 0x10000000 Mar 30 16:08 tinyvol.p0
    drwxr-xr-x  2 root  wheel       512 Mar 30 16:08 tinyvol.p0.sd
    /dev/vinum/vol/tinyvol.plex/tinyvol.p0.sd:
    total 0
    brwxr-xr--  1 root  wheel   25, 0x20000000 Mar 30 16:08 tinyvol.p0.s0
    brwxr-xr--  1 root  wheel   25, 0x20100000 Mar 30 16:08 tinyvol.p0.s1
    /dev/vinum/vol/vol5.plex:
    total 2
    brwxr-xr--  1 root  wheel   25, 0x10000004 Mar 30 16:08 vol5.p0
    drwxr-xr-x  2 root  wheel       512 Mar 30 16:08 vol5.p0.sd
    brwxr-xr--  1 root  wheel   25, 0x10010004 Mar 30 16:08 vol5.p1
    drwxr-xr-x  2 root  wheel       512 Mar 30 16:08 vol5.p1.sd
    /dev/vinum/vol/vol5.plex/vol5.p0.sd:
    total 0
    brwxr-xr--  1 root  wheel   25, 0x20000004 Mar 30 16:08 vol5.p0.s0
    brwxr-xr--  1 root  wheel   25, 0x20100004 Mar 30 16:08 vol5.p0.s1
    /dev/vinum/vol/vol5.plex/vol5.p1.sd:
    total 0
    brwxr-xr--  1 root  wheel   25, 0x20010004 Mar 30 16:08 vol5.p1.s0
    brwxr-xr--  1 root  wheel   25, 0x20110004 Mar 30 16:08 vol5.p1.s1
    /dev/rvinum:
    crwxr-xr--  1 root  wheel   91,   2 Mar 30 16:08 rconcat
    crwxr-xr--  1 root  wheel   91,   3 Mar 30 16:08 rstrcon
    crwxr-xr--  1 root  wheel   91,   1 Mar 30 16:08 rstripe
    crwxr-xr--  1 root  wheel   91,   0 Mar 30 16:08 rtinyvol
    crwxr-xr--  1 root  wheel   91,   4 Mar 30 16:08 rvol5

In the case of unattached plexes and subdisks, the naming is reversed. Subdisks are named after the disk on which they are located, and plexes are named after the subdisk. This mapping is still to be determined.

  OBJECT STATES

Each vinum object has a state associated with it. vinum uses this state to determine the handling of the object.

  VOLUME STATES
Volumes may have the following states:

volume_down
    The volume is completely inaccessible.

volume_up
    The volume is up and at least partially functional. Not all plexes may be available.

  PLEX STATES
Plexes may have the following states:

faulty
    A plex which has gone completely down because of I/O errors.

down
    A plex which has been taken down by the administrator.

initializing
    A plex which is being initialized.

    The remaining states represent plexes which are at least partially up.

corrupt
    A plex entry which is at least partially up. Not all subdisks are available, and an inconsistency has occurred. If no other plex is uncorrupted, the volume is no longer consistent.

degraded
    A RAID-5 plex entry which is accessible, but one subdisk is down, requiring recovery for many I/O requests.

flaky
    A plex which is really up, but which has a reborn subdisk which we don't completely trust, and which we don't want to read if we can avoid it.

up  A plex entry which is completely up. All subdisks are up.

  SUBDISK STATES
Subdisks can have the following states:

empty
    A subdisk entry which has been created completely. All fields are correct, and the disk has been updated, but there is no data on the disk.

initializing
    A subdisk entry which has been created completely and which is currently being initialized.

    The following states represent invalid data.

obsolete
    A subdisk entry which has been created completely. All fields are correct, the config on disk has been updated, and the data was valid, but since then the drive has been taken down, and as a result updates have been missed.

stale
    A subdisk entry which has been created completely. All fields are correct, the disk has been updated, and the data was valid, but since then the drive has been crashed and updates have been lost.

    The following states represent valid, inaccessible data.

crashed
    A subdisk entry which has been created completely. All fields are correct, the disk has been updated, and the data was valid, but since then the drive has gone down. No attempt has been made to write to the subdisk since the crash, so the data is valid.

down
    A subdisk entry which was up, which contained valid data, and which was taken down by the administrator. The data is valid.

reviving
    The subdisk is currently in the process of being revived. We can write but not read.

    The following states represent accessible subdisks with valid data.

reborn
    A subdisk entry which has been created completely. All fields are correct, the disk has been updated, and the data was valid, but since then the drive has gone down and up again. No updates were lost, but it is possible that the subdisk has been damaged. We won't read from this subdisk if we have a choice. If this is the only subdisk which covers this address space in the plex, we set its state to up under these circumstances, so this status implies that there is another subdisk to fulfil the request.

up  A subdisk entry which has been created completely. All fields are correct, the disk has been updated, and the data is valid.

  DRIVE STATES
Drives can have the following states:

down
    The drive is not accessible.

up  The drive is up and running.

BUGS AND OMISSIONS

1.  vinum is a new product. Some bugs can be expected. The configuration mechanism is not yet fully functional. If you have difficulties, please look at http://www.lemis.com/vinum_beta.html and http://www.lemis.com/vinum_debugging.html before reporting problems.

2.  It is possible to unload the vinum module with the modunload command. This is buggy, and the only reason it is present at all is to make it easier for people testing the system: the alternative is a reboot. It works about 80% of the time: expect about one panic every five unloads.

3.  It is possible to configure vinum statically, but it has never been tested in this form. Don't even bother to report the problem if you have trouble with a static vinum pseudo-device, unless you can also repeat it with the LKM.

4.  It is necessary to initialize RAID-5 plexes. Failure to do so will not impede normal operation, but it will cause complete corruption if one of the disks should fail. I don't know any good way to enforce this initialization (or the even slower alternative of rebuilding the parity blocks). If anybody has a good idea, I'd be grateful for input.

5.  Detection of differences between the version of the kernel and the LKM is not yet implemented.

6.  This version of vinum has been backported to FreeBSD 2.2-STABLE. No further work will be done on this version, and debugging facilities are much worse than with the version of vinum in FreeBSD 3.0. It is unlikely that any problems in this version will be fixed unless they also occur in FreeBSD 3.0.

DEBUGGING PROBLEMS WITH VINUM

Solving problems with vinum can be a difficult affair. This section suggests some approaches.

  Configuration problems

It is relatively easy (too easy) to run into problems with the vinum configuration. If you do, the first thing you should do is stop configuration updates:

    # vinum setdaemon 4

This will stop updates and any further corruption of the on-disk configuration.

Next, look at the on-disk configuration, using a Bourne-style shell:

    # rm -f log
    # for i in /dev/da0s1h /dev/da1s1h /dev/da2s1h /dev/da3s1h; do
    >    (dd if=/dev/da1h skip=8 count=6|tr -d '\000-\011\200-\377'; echo) >> log
    >  done

The names of the devices are the names of all vinum slices. The file log should then contain something like this:

    IN VINOpanic.lemis.comdrive1}6E7~^K6T^Yfoovolume obj state up
    volume src state up
    volume raid state down
    volume r state down
    volume foo state up
    plex name obj.p0 state corrupt org concat vol obj
    plex name obj.p1 state corrupt org striped 128b vol obj
    plex name src.p0 state corrupt org striped 128b vol src
    plex name src.p1 state up org concat vol src
    plex name raid.p0 state faulty org disorg vol raid
    plex name r.p0 state faulty org disorg vol r
    plex name foo.p0 state up org concat vol foo
    plex name foo.p1 state faulty org concat vol foo
    sd name obj.p0.s0 drive drive2 plex obj.p0 state reborn len 409600b driveoffset 265b plexoffset 0b
    sd name obj.p0.s1 drive drive4 plex obj.p0 state up len 409600b driveoffset 265b plexoffset 409600b
    sd name obj.p1.s0 drive drive1 plex obj.p1 state up len 204800b driveoffset 265b plexoffset 0b
    sd name obj.p1.s1 drive drive2 plex obj.p1 state reborn len 204800b driveoffset 409865b plexoffset 128b
    sd name obj.p1.s2 drive drive3 plex obj.p1 state up len 204800b driveoffset 265b plexoffset 256b
    sd name obj.p1.s3 drive drive4 plex obj.p1 state up len 204800b driveoffset 409865b plexoffset 384b

The first line contains the vinum label and must start with the text IN VINO. It also contains the name of the system. The exact definition is contained in /usr/src/sys/dev/vinum/vinumvar.h. The saved configuration starts in the middle of the line with the text volume obj state up and starts in sector 9 of the disk. The rest of the output shows the remainder of the on-disk configuration. It may be necessary to increase the count argument of dd in order to see the complete configuration.

The configuration on all disks should be the same. If this is not the case, please report the problem with the exact contents of the file log. There is probably little that can be done to recover the on-disk configuration, but if you keep a copy of the files used to create the objects, you should be able to re-create them. The create command does not change the subdisk data, so this will not cause data corruption. You may need to use the resetconfig command if you have this kind of trouble.

  Kernel Panics

In FreeBSD 3.0 and later, vinum contains specific support for debugging panics. The version in FreeBSD 2.2 does not contain much of this support, and debugging is much more difficult. If you have a problem with this version, please report it and try to reproduce it under FreeBSD 3.0 or later if possible.

AUTHOR
Greg Lehey <grog@lemis.com>.

HISTORY
vinum first appeared in FreeBSD 3.0.

SEE ALSO
vinum(8), disklabel(5), disklabel(8).