vinum -- Logical Volume Manager
kldload vinum
vinum is a logical volume manager inspired by, but not derived from, the
Veritas Volume Manager. It provides the following features:
+o It provides device-independent logical disks, called volumes. Volumes
are not restricted to the size of any disk on the system.
+o 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:
+o 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.
+o 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.
+o 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.
+o 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.
+o 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).
+o A number of mappings between subdisks and plexes are available:
+o Concatenated plexes consist of one or more subdisks, each of
which is mapped to a contiguous part of the plex address space.
+o 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.
+o 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.
+o Drives are the lowest level of the storage hierarchy. They represent
disk special devices.
+o 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 Veritastm 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.
vinum is currently supplied as a KLD module, and does not require configuration.
As with other KLDs, it is absolutely necessary to match the KLD
to the version of the operating system. Failure to do so will cause
vinum to issue an error message and terminate.
It is possible to configure vinum in the kernel, but this is not recommended.
To do so, add this line to the kernel configuration file:
device vinum
Debug Options [Toc] [Back]
The current version of vinum, both the kernel module and the user program
vinum(8), include significant debugging support. It is not recommended
to remove this support at the moment, but if you do you must remove it
from both the kernel and the user components. To do this, edit the files
/usr/src/sbin/vinum/Makefile and /usr/src/sys/modules/vinum/Makefile and
edit the CFLAGS variable to remove the -DVINUMDEBUG option. If you have
configured vinum into the kernel, either specify the line
options VINUMDEBUG
in the kernel configuration file or remove the -DVINUMDEBUG option from
/usr/src/sbin/vinum/Makefile as described above.
If the VINUMDEBUG variables do not match, vinum(8) will fail with a message
explaining the problem and what to do to correct it.
Other Options [Toc] [Back]
options VINUM_AUTOSTART
Make vinum automatically scan all available disks at attach time. This
is a deprecated way that is primarily intended for environments that do
not want to rely on kernel environment variables set by loader(8).
vinum was previously available in two versions: a freely available version
which did not contain RAID-5 functionality, and a full version
including RAID-5 functionality, which was available only from Cybernet
Systems Inc. The present version of vinum includes the RAID-5 functionality.
vinum is part of the base FreeBSD system. It does not require installation.
To start it, start the vinum(8) program, which will load the KLD
if it is not already present. Before using vinum, it must be configured.
See vinum(8) for information on how to create a vinum configuration.
Normally, you start a configured version of vinum at boot time. Set the
variable start_vinum in /etc/rc.conf to ``YES'' to start vinum at boot
time. (See rc.conf(5) for more details.)
If vinum is loaded as a KLD (the recommended way), the vinum stop command
will unload it (see vinum(8)). You can also do this with the
kldunload(8) command.
The KLD can only be unloaded when idle, in other words when no volumes
are mounted and no other instances of the vinum(8) program are active.
Unloading the KLD does not harm the data in the volumes.
Configuring and Starting Objects [Toc] [Back]
Use the vinum(8) utility to configure and start vinum objects.
The vinum subsystem can be automatically started at attach time. There
are two kernel environment variables that can be set in loader.conf(5) to
accomplish this.
vinum.autostart If this variable is set (to any value), the attach
function will attempt to scan all available disks
for valid vinum configuration records. This is
the preferred way if automatic startup is desired.
Example:
vinum.autostart="YES"
vinum.drives Alternatively, this variable can enumerate a list
of disk devices to scan for configuration records.
Note that only the ``bare'' device names need to
be given, since vinum will automatically scan all
possible slices and partitions.
Example:
vinum.drives="da0 da1"
If automatic startup is used, it is not necessary to set the start_vinum
variable of rc.conf(5). Note that if vinum is to supply to the volume
for the root file system, it is necessary to start the subsystem early.
This can be achieved by specifying
vinum_load="YES"
in loader.conf(5).
ioctl(2) calls are intended for the use of the vinum(8) configuration
program only. They are described in the header file
/sys/dev/vinum/vinumio.h.
Disk Labels [Toc] [Back]
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.
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(8) will complain that it cannot determine
the partition. To solve this problem, use the -v flag to newfs(8). For
example, if you have a volume concat, use the following command to create
a UFS file system on it:
newfs -v /dev/vinum/concat
vinum assigns default names to plexes and subdisks, although they may be
overridden. We do not recommend overriding the default names. Experience
with the Veritastm volume manager, which allows arbitrary 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
subdisk names are longer than the name from which they are derived.
+o When vinum 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 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.
+o In addition, vinum creates three super-devices, /dev/vinum/control,
/dev/vinum/Control and /dev/vinum/controld. /dev/vinum/control is
used by vinum(8) when it has been compiled without the VINUMDEBUG
option, /dev/vinum/Control is used by vinum(8) when it has been compiled
with the VINUMDEBUG option, and /dev/vinum/controld is used by
the vinum daemon. The two control devices for vinum(8) are used to
synchronize the debug status of kernel and user modules.
+o 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(8), 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(8) in order to tell it to
ignore this convention.
+o 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.
+o 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.
+o 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 [Toc] [Back]
Assume the vinum objects described in the section CONFIGURATION FILE in
vinum(8). The directory /dev/vinum looks like:
# ls -lR /dev/vinum
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
brwx------ 1 root wheel 25, 0x40000001 Mar 30 16:08 controld
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/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
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 [Toc] [Back]
Each vinum object has a state associated with it. vinum uses this state
to determine the handling of the object.
Volume States [Toc] [Back]
Volumes may have the following states:
down The volume is completely inaccessible.
up The volume is up and at least partially functional. Not
all plexes may be available.
Plex States [Toc] [Back]
Plexes may have the following states:
referenced A plex entry which has been referenced as part of a volume,
but which is currently not known.
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 do not completely trust, and which we do not
want to read if we can avoid it.
up A plex entry which is completely up. All subdisks are
up.
Subdisk States [Toc] [Back]
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
the on the disk is not valid.
referenced A subdisk entry which has been referenced as part of a
plex, but which is currently not known.
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 will not 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 fulfill
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 [Toc] [Back]
Drives can have the following states:
referenced At least one subdisk refers to the drive, but it is not
currently accessible to the system. No device name is
known.
down The drive is not accessible.
up The drive is up and running.
vinum is a new product. Bugs can be expected. The configuration mechanism
is not yet fully functional. If you have difficulties, please look
at the section DEBUGGING PROBLEMS WITH VINUM before reporting problems.
Kernels with the vinum device appear to work, but are not supported. If
you have trouble with this configuration, please first replace the kernel
with a non-vinum kernel and test with the KLD module.
Detection of differences between the version of the kernel and the KLD is
not yet implemented.
The RAID-5 functionality is new in FreeBSD 3.3. Some problems have been
reported with vinum in combination with soft updates, but these are not
reproducible on all systems. If you are planning to use vinum in a production
environment, please test carefully.
DEBUGGING PROBLEMS WITH VINUM [Toc] [Back] Solving problems with vinum can be a difficult affair. This section suggests
some approaches.
Configuration problems [Toc] [Back]
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=$i 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(1) 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 [Toc] [Back]
In order to analyse a panic which you suspect comes from vinum you will
need to build a debug kernel. See the online handbook at
/usr/share/doc/en/books/developers-handbook/kerneldebug.html (if
installed) or
http://www.FreeBSD.org/doc/en_US.ISO8859-1/books/developers--
handbook/kerneldebug.html for more details of how to do this.
Perform the following steps to analyse a vinum problem:
1. Copy the files /usr/src/sys/modules/vinum/.gdbinit.crash,
/usr/src/sys/modules/vinum/.gdbinit.kernel,
/usr/src/sys/modules/vinum/.gdbinit.serial,
/usr/src/sys/modules/vinum/.gdbinit.vinum and
/usr/src/sys/modules/vinum/.gdbinit.vinum.paths to the directory in
which you will be performing the analysis, typically /var/crash.
2. Make sure that you build the vinum module with debugging information.
The standard Makefile builds a module with debugging symbols
by default. If the version of vinum in /boot/kernel does not contain
symbols, you will not get an error message, but the stack trace
will not show the symbols. Check the module before starting gdb(1):
$ file /boot/kernel/vinum.ko
/boot/kernel/vinum.ko: ELF 32-bit LSB shared object, Intel 80386,
version 1 (FreeBSD), not stripped
If the output shows that /boot/kernel/vinum.ko is stripped, you will
have to find a version which is not. Usually this will be either in
/usr/obj/sys/modules/vinum/vinum.ko (if you have built vinum with a
``make world'') or /usr/src/sys/modules/vinum/vinum.ko (if you have
built vinum in this directory). Modify the file
.gdbinit.vinum.paths accordingly.
3. Either take a dump or use remote serial gdb(1) to analyse the problem.
To analyse a dump, say /var/crash/vmcore.5, link
/var/crash/.gdbinit.crash to /var/crash/.gdbinit and enter:
cd /var/crash
gdb -k kernel.debug vmcore.5
This example assumes that you have installed the correct debug kernel
at /var/crash/kernel.debug. If not, substitute the correct name
of the debug kernel.
To perform remote serial debugging, link /var/crash/.gdbinit.serial
to /var/crash/.gdbinit and enter
cd /var/crash
gdb -k kernel.debug
In this case, the .gdbinit file performs the functions necessary to
establish connection. The remote machine must already be in debug
mode: enter the kernel debugger and select gdb (see ddb(4) for more
details). The serial .gdbinit file expects the serial connection to
run at 38400 bits per second; if you run at a different speed, edit
the file accordingly (look for the remotebaud specification).
The following example shows a remote debugging session using the
debug command of vinum(8):
GDB 4.16 (i386-unknown-freebsd), Copyright 1996 Free Software Foundation, Inc.
Debugger (msg=0xf1093174 "vinum debug") at ../../i386/i386/db_interface.c:318
318 in_Debugger = 0;
#1 0xf108d9bc in vinumioctl (dev=0x40001900, cmd=0xc008464b, data=0xf6dedee0 "",
flag=0x3, p=0xf68b7940) at
/usr/src/sys/modules/Vinum/../../dev/Vinum/vinumioctl.c:102
102 Debugger ("vinum debug");
(kgdb) bt
#0 Debugger (msg=0xf0f661ac "vinum debug") at ../../i386/i386/db_interface.c:318
#1 0xf0f60a7c in vinumioctl (dev=0x40001900, cmd=0xc008464b, data=0xf6923ed0 "",
flag=0x3, p=0xf688e6c0) at
/usr/src/sys/modules/vinum/../../dev/vinum/vinumioctl.c:109
#2 0xf01833b7 in spec_ioctl (ap=0xf6923e0c) at ../../miscfs/specfs/spec_vnops.c:424
#3 0xf0182cc9 in spec_vnoperate (ap=0xf6923e0c) at ../../miscfs/specfs/spec_vnops.c:129
#4 0xf01eb3c1 in ufs_vnoperatespec (ap=0xf6923e0c) at ../../ufs/ufs/ufs_vnops.c:2312
#5 0xf017dbb1 in vn_ioctl (fp=0xf1007ec0, com=0xc008464b, data=0xf6923ed0 "",
p=0xf688e6c0) at vnode_if.h:395
#6 0xf015dce0 in ioctl (p=0xf688e6c0, uap=0xf6923f84) at ../../kern/sys_generic.c:473
#7 0xf0214c0b in syscall (frame={tf_es = 0x27, tf_ds = 0x27, tf_edi = 0xefbfcff8,
tf_esi = 0x1, tf_ebp = 0xefbfcf90, tf_isp = 0xf6923fd4, tf_ebx = 0x2,
tf_edx = 0x804b614, tf_ecx = 0x8085d10, tf_eax = 0x36, tf_trapno = 0x7,
tf_err = 0x2, tf_eip = 0x8060a34, tf_cs = 0x1f, tf_eflags = 0x286,
tf_esp = 0xefbfcf78, tf_ss = 0x27}) at ../../i386/i386/trap.c:1100
#8 0xf020a1fc in Xint0x80_syscall ()
#9 0x804832d in ?? ()
#10 0x80482ad in ?? ()
#11 0x80480e9 in ?? ()
When entering from the debugger, it is important that the source of
frame 1 (listed by the .gdbinit file at the top of the example) contains
the text ``Debugger ("vinum debug");''.
This is an indication that the address specifications are correct.
If you get some other output, your symbols and the kernel module are
out of sync, and the trace will be meaningless.
For an initial investigation, the most important information is the output
of the bt (backtrace) command above.
Reporting Problems with Vinum [Toc] [Back]
If you find any bugs in vinum, please report them to Greg Lehey
<[email protected]>. Supply the following information:
+o The output of the vinum list command (see vinum(8)).
+o Any messages printed in /var/log/messages. All such messages will be
identified by the text ``vinum'' at the beginning.
+o If you have a panic, a stack trace as described above.
Greg Lehey <[email protected]>.
vinum first appeared in FreeBSD 3.0. The RAID-5 component of vinum was
developed by Cybernet Inc. (http://www.cybernet.com/), for its NetMAX
product.
disklabel(5), loader.conf(5), disklabel(8), loader(8), newfs(8), vinum(8)
FreeBSD 5.2.1 May 16, 2002 FreeBSD 5.2.1 [ Back ] |
