53d349a107
spares, and rebuilding components in-place. Re-arrange the letters/options to make more sense (and make better use of the alphabet).
749 lines
22 KiB
Groff
749 lines
22 KiB
Groff
.\" $NetBSD: raidctl.8,v 1.5 1999/03/02 03:13:59 oster Exp $
|
|
.\"
|
|
.\" Copyright (c) 1998 The NetBSD Foundation, Inc.
|
|
.\" All rights reserved.
|
|
.\"
|
|
.\" This code is derived from software contributed to The NetBSD Foundation
|
|
.\" by Greg Oster
|
|
.\"
|
|
.\" Redistribution and use in source and binary forms, with or without
|
|
.\" modification, are permitted provided that the following conditions
|
|
.\" are met:
|
|
.\" 1. Redistributions of source code must retain the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer.
|
|
.\" 2. Redistributions in binary form must reproduce the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer in the
|
|
.\" documentation and/or other materials provided with the distribution.
|
|
.\" 3. All advertising materials mentioning features or use of this software
|
|
.\" must display the following acknowledgement:
|
|
.\" This product includes software developed by the NetBSD
|
|
.\" Foundation, Inc. and its contributors.
|
|
.\" 4. Neither the name of The NetBSD Foundation nor the names of its
|
|
.\" contributors may be used to endorse or promote products derived
|
|
.\" from this software without specific prior written permission.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
|
|
.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
|
|
.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
|
|
.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
|
|
.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
|
|
.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
|
|
.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
|
|
.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
|
|
.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
|
|
.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
|
|
.\" POSSIBILITY OF SUCH DAMAGE.
|
|
.\"
|
|
.\"
|
|
.\" Copyright (c) 1995 Carnegie-Mellon University.
|
|
.\" All rights reserved.
|
|
.\"
|
|
.\" Author: Mark Holland
|
|
.\"
|
|
.\" Permission to use, copy, modify and distribute this software and
|
|
.\" its documentation is hereby granted, provided that both the copyright
|
|
.\" notice and this permission notice appear in all copies of the
|
|
.\" software, derivative works or modified versions, and any portions
|
|
.\" thereof, and that both notices appear in supporting documentation.
|
|
.\"
|
|
.\" CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
|
|
.\" CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
|
|
.\" FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
|
|
.\"
|
|
.\" Carnegie Mellon requests users of this software to return to
|
|
.\"
|
|
.\" Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
|
|
.\" School of Computer Science
|
|
.\" Carnegie Mellon University
|
|
.\" Pittsburgh PA 15213-3890
|
|
.\"
|
|
.\" any improvements or extensions that they make and grant Carnegie the
|
|
.\" rights to redistribute these changes.
|
|
.\"
|
|
.Dd November 6, 1998
|
|
.Dt RAIDCTL 8
|
|
.Os NetBSD
|
|
.Sh NAME
|
|
.Nm raidctl
|
|
.Nd configuration utility for the RAIDframe disk driver
|
|
.Sh SYNOPSIS
|
|
.Nm ""
|
|
.Fl a Ar component Ar dev
|
|
.Nm ""
|
|
.Fl B Ar dev
|
|
.Nm ""
|
|
.Fl c Ar config_file Ar dev
|
|
.Nm ""
|
|
.Fl C Ar config_file Ar dev
|
|
.Nm ""
|
|
.Fl f Ar component Ar dev
|
|
.Nm ""
|
|
.Fl F Ar component Ar dev
|
|
.Nm ""
|
|
.Fl g Ar component Ar dev
|
|
.Nm ""
|
|
.Fl i Ar dev
|
|
.Nm ""
|
|
.Fl I Ar serial_number Ar dev
|
|
.Nm ""
|
|
.Fl r Ar component Ar dev
|
|
.Nm ""
|
|
.Fl R Ar component Ar dev
|
|
.Nm ""
|
|
.Fl s Ar dev
|
|
.Nm ""
|
|
.Fl S Ar dev
|
|
.Nm ""
|
|
.Fl u Ar dev
|
|
.Sh DESCRIPTION
|
|
.Nm ""
|
|
is the user-land control program for
|
|
.Xr raid 4 , Ns
|
|
the RAIDframe disk device.
|
|
.Nm ""
|
|
is primarily used to dynamically configure and unconfigure RAIDframe disk
|
|
devices. For more information about the RAIDframe disk device, see
|
|
.Xr raid 4 .
|
|
.Pp
|
|
This document assumes the reader has at least rudimentary knowledge of
|
|
RAID and RAID concepts.
|
|
.Pp
|
|
The command-line options for
|
|
.Nm
|
|
are as follows:
|
|
.Bl -tag -width indent
|
|
.It Fl a Ar component Ar dev
|
|
Add
|
|
.Ar component
|
|
as a hot spare for the device
|
|
.Ar dev .
|
|
.It Fl B Ar dev
|
|
Initiate a copyback of reconstructed data from a spare disk to
|
|
it's original disk. This is performed after a component has failed,
|
|
and the failed drive has been reconstructed onto a spare drive.
|
|
.It Fl c Ar config_file Ar dev
|
|
Configure the RAIDframe device
|
|
.Ar dev
|
|
according to the configuration given in
|
|
.Ar config_file .
|
|
A description of the contents of
|
|
.Ar config_file
|
|
is given later.
|
|
.It Fl C Ar config_file Ar dev
|
|
As for
|
|
.Ar -c ,
|
|
but forces the configuration to take place. This is required the
|
|
first time a RAID set is configured.
|
|
.It Fl f Ar component Ar dev
|
|
This marks the specified
|
|
.Ar component
|
|
as having failed, but does not initiate a reconstruction of that
|
|
component.
|
|
.It Fl F Ar component Ar dev
|
|
Fails the specified
|
|
.Ar component
|
|
of the device, and immediately begin a reconstruction of the failed
|
|
disk onto an available hot spare. This is one of the mechanisms used to start
|
|
the reconstruction process if a component does have a hardware failure.
|
|
.It Fl g Ar component Ar dev
|
|
Get the component label for the specified component.
|
|
.It Fl i Ar dev
|
|
Initialize (re-write) the parity on the device. This
|
|
.Ar MUST
|
|
be done before the RAID device is labeled and before
|
|
filesystems are created on the RAID device, and is normally used after
|
|
a system crash (and before a
|
|
.Xr fsck 8 ) Ns
|
|
to ensure the integrity of the parity.
|
|
.It Fl I Ar serial_number Ar dev
|
|
Initialize the component labels on each component of the device.
|
|
.Ar serial_number
|
|
is used as one of the keys in determining whether a
|
|
particular set of components belong to the same RAID set. While not
|
|
strictly enforced, different serial numbers should be used for
|
|
different RAID sets.
|
|
.It Fl r Ar component Ar dev
|
|
Remove the spare disk specified by
|
|
.Ar component
|
|
from the set of available spare components.
|
|
.It Fl R Ar component Ar dev
|
|
Fails the specified
|
|
.Ar component ,
|
|
if necessary, and immediately begins a reconstruction back to
|
|
.Ar component .
|
|
This is another mechanism for starting the reconstruction process if a
|
|
component has a hardware failure.
|
|
.It Fl s Ar dev
|
|
Display the status of the RAIDframe device for each of the components
|
|
and spares.
|
|
.It Fl S Ar dev
|
|
Check the status of component reconstruction. The output indicates
|
|
the amount of progress achieved in reconstructing a failed component.
|
|
.It Fl u Ar dev
|
|
Unconfigure the RAIDframe device.
|
|
.El
|
|
.Pp
|
|
The device used by
|
|
.Nm
|
|
is specified by
|
|
.Ar dev .
|
|
.Ar dev
|
|
may be either the full name of the device, e.g. /dev/rraid0d,
|
|
for the i386 architecture, and /dev/rraid0c
|
|
for all others, or just simply raid0 (for /dev/rraid0d).
|
|
.Pp
|
|
The format of the configuration file is complex, and
|
|
only an abbreviated treatment is given here. In the configuration
|
|
files, a
|
|
.Sq #
|
|
indicates the beginning of a comment.
|
|
.Pp
|
|
There are 4 required sections of a configuration file, and 2
|
|
optional components. Each section begins with a
|
|
.Sq START ,
|
|
followed by
|
|
the section name, and the confuration parameters associated with that
|
|
section. The first section is the
|
|
.Sq array
|
|
section, and it specifies
|
|
the number of rows, columns, and spare disks in the RAID set. For
|
|
example:
|
|
.Bd -unfilled -offset indent
|
|
START array
|
|
1 3 0
|
|
.Ed
|
|
.Pp
|
|
indicates an array with 1 row, 3 columns, and 0 spare disks. Note
|
|
that although multi-dimenstional arrays may be specified, they are
|
|
.Ar NOT
|
|
supported in the driver.
|
|
.Pp
|
|
The second section, the
|
|
.Sq disks
|
|
section, specifies the actual
|
|
components of the device. For example:
|
|
.Bd -unfilled -offset indent
|
|
START disks
|
|
/dev/sd0e
|
|
/dev/sd1e
|
|
/dev/sd2e
|
|
.Ed
|
|
.Pp
|
|
specifies the three component disks to be used in the RAID device. If
|
|
any of the specified drives cannot be found when the RAID device is
|
|
configured, then they will be marked as
|
|
.Sq failed ,
|
|
and the system will
|
|
operate in degraded mode. Note that it is
|
|
.Ar imperative
|
|
that the order of the components in the configuration file does not
|
|
change between configurations of a RAID device. Changing the order
|
|
of the components (at least at the time of this writing) will result in
|
|
data loss.
|
|
.Pp
|
|
The next section, which is the
|
|
.Sq spare
|
|
section, is optional, and, if
|
|
present, specifies the devices to be used as
|
|
.Sq hot spares
|
|
-- devices
|
|
which are on-line, but are not actively used by the RAID driver unless
|
|
one of the main components fail. A simple
|
|
.Sq spare
|
|
section might be:
|
|
.Bd -unfilled -offset indent
|
|
START spare
|
|
/dev/sd3e
|
|
.Ed
|
|
.Pp
|
|
for a configuration with a single spare component. If no spare drives
|
|
are to be used in the configuration, then the
|
|
.Sq spare
|
|
section may be omitted.
|
|
.Pp
|
|
The next section is the
|
|
.Sq layout
|
|
section. This section describes the
|
|
general layout parameters for the RAID device, and provides such
|
|
information as sectors per stripe unit, stripe units per parity unit,
|
|
stripe units per reconstruction unit, and the parity configuration to
|
|
use. This section might look like:
|
|
.Bd -unfilled -offset indent
|
|
START layout
|
|
# sectPerSU SUsPerParityUnit SUsPerReconUnit RAID_level
|
|
32 1 1 5
|
|
.Ed
|
|
.Pp
|
|
The sectors per stripe unit specifies, in blocks, the interleave
|
|
factor; i.e. the number of contiguous sectors to be written to each
|
|
component for a single stripe. Appropriate selection of this value
|
|
(32 in this example) is the subject of much research in RAID
|
|
architectures. The stripe units per parity unit and
|
|
stripe units per reconstruction unit are normally each set to 1.
|
|
While certain values above 1 are permitted, a discussion of valid
|
|
values and the consequences of using anything other than 1 are outside
|
|
the scope of this document. The last value in this section (5 in this
|
|
example) indicates the parity configuration desired. Valid entries
|
|
include:
|
|
.Bl -tag -width inde
|
|
.It 0
|
|
RAID level 0. No parity, only simple striping.
|
|
.It 1
|
|
RAID level 1. Mirroring.
|
|
.It 4
|
|
RAID level 4. Striping across components, with parity stored on the
|
|
last component.
|
|
.It 5
|
|
RAID level 5. Striping across components, parity distributed across
|
|
all components.
|
|
.El
|
|
.Pp
|
|
There are other valid entries here, including those for Even-Odd
|
|
parity, RAID level 5 with rotated sparing, Chained declustering,
|
|
and Interleaved declustering, but as of this writing the code for
|
|
those parity operations has not been tested with
|
|
.Nx .
|
|
.Pp
|
|
The next required section is the
|
|
.Sq queue
|
|
section. This is most often
|
|
specified as:
|
|
.Bd -unfilled -offset indent
|
|
START queue
|
|
fifo 1
|
|
.Ed
|
|
.Pp
|
|
where the queueing method is specified as fifo (first-in, first-out),
|
|
and the size of the per-component queue is limited to 1 requests. A
|
|
value of 1 is quite conservative here, and values of 100 or more may
|
|
been used to increase the driver performance.
|
|
Other queuing methods may also be specified, but a discussion of them
|
|
is beyond the scope of this document.
|
|
.Pp
|
|
The final section, the
|
|
.Sq debug
|
|
section, is optional. For more details
|
|
on this the reader is referred to the RAIDframe documentation
|
|
dissussed in the
|
|
.Sx HISTORY
|
|
section.
|
|
|
|
See
|
|
.Sx EXAMPLES
|
|
for a more complete configuration file example.
|
|
|
|
.Sh EXAMPLES
|
|
|
|
The examples in this section will focus on a RAID 5 configuration.
|
|
Other RAID configurations will behave similarly. It is highly
|
|
recommended that before using the RAID driver for real filesystems
|
|
that the system administrator(s) have used
|
|
.Ar all
|
|
of the options for
|
|
.Nm "" ,
|
|
and that they understand how the component reconstruction process
|
|
works. While this example is not created as a tutorial, the steps
|
|
shown here can be easily dupilicated using four equal-sized partitions
|
|
from any number of disks (including all four from a single disk).
|
|
.Pp
|
|
The primary uses of
|
|
.Nm ""
|
|
is to configure and unconfigure
|
|
.Xr raid 4
|
|
devices. To configure the device, a configuration
|
|
file which looks something like:
|
|
.Bd -unfilled -offset indent
|
|
START array
|
|
# numRow numCol numSpare
|
|
1 3 1
|
|
|
|
START disks
|
|
/dev/sd1e
|
|
/dev/sd2e
|
|
/dev/sd3e
|
|
|
|
START spare
|
|
/dev/sd4e
|
|
|
|
START layout
|
|
# sectPerSU SUsPerParityUnit SUsPerReconUnit RAID_level_5
|
|
32 1 1 5
|
|
|
|
START queue
|
|
fifo 100
|
|
.Ed
|
|
.Pp
|
|
is first created. In short, this configuration file specifies a RAID
|
|
5 configuration consisting of the components /dev/sd1e,
|
|
/dev/sd2e, and /dev/sd3e, with /dev/sd4e available as a
|
|
.Sq hot spare
|
|
in case one of
|
|
the three main drives should fail. If the above configuration is in a
|
|
file called
|
|
.Sq rfconfig ,
|
|
raid device 0 in the normal case can be configured with:
|
|
.Bd -unfilled -offset indent
|
|
raidctl -c rfconfig raid0
|
|
.Ed
|
|
.Pp
|
|
The above is equivalent to the following:
|
|
.Bd -unfilled -offset indent
|
|
raidctl -c rfconfig /dev/rraid0d
|
|
.Ed
|
|
.Pp
|
|
on the i386 architecture. On all other architectures, /dev/rraid0c
|
|
is used in place of /dev/rraid0d.
|
|
.Pp
|
|
A RAID set will not configure with
|
|
.Fl c
|
|
if the component labels are not correct. A
|
|
.Sq component label
|
|
contains important information about the component, including a
|
|
user-specified serial number, the row and column of that component in the RAID
|
|
set, and whether the data (and parity) on the component is
|
|
.Sq clean .
|
|
See
|
|
.Xr raid 4
|
|
for more information about component labels.
|
|
.Pp
|
|
Since new RAID sets will not have correct component labels, the first
|
|
configuration of a RAID set must use
|
|
.Fl C
|
|
instead of
|
|
.Fl c :
|
|
.Bd -unfilled -offset indent
|
|
raidctl -C rfconfig raid0
|
|
.Ed
|
|
.Pp
|
|
The
|
|
.Fl C
|
|
forces the configuration to succeed, even if any of the component
|
|
labels are incorrect. This option should not be used lightly in
|
|
situations other than initial configurations, as if
|
|
the system is refusing to configure a RAID set, there is probably a
|
|
very good reason for it.
|
|
.Pp
|
|
When the RAID set is configured for the first time, it is
|
|
necessary to initialize the component labels, and to initialize the
|
|
parity on the RAID set. Initializing the component labels is done with:
|
|
.Bd -unfilled -offset indent
|
|
raidctl -I 112341 raid0
|
|
.Ed
|
|
.Pp
|
|
where
|
|
.Sq 112341
|
|
is a user-specified serial number for the RAID set. Using different
|
|
serial numbers between RAID sets is strongly encouraged, as using the
|
|
same serial number for all RAID sets will only serve to decrease the
|
|
usefulness of the component label checking.
|
|
.Pp
|
|
Initializing the parity on the RAID set is done via:
|
|
.Bd -unfilled -offset indent
|
|
raidctl -i raid0
|
|
.Ed
|
|
.Pp
|
|
Initializing the parity in this way may also be required after an
|
|
unclean shutdown. Once the parity is known to be correct,
|
|
it is then safe to perform
|
|
.Xr disklabel 8 , Ns
|
|
.Xr newfs 8 , Ns
|
|
or
|
|
.Xr fsck 8
|
|
on the device or its filesystems, and then to mount the filesystems
|
|
for use.
|
|
.Pp
|
|
To see how the RAID set is doing, the following command can be used to
|
|
show the RAID set's status:
|
|
.Bd -unfilled -offset indent
|
|
raidctl -s raid0
|
|
.Ed
|
|
.Pp
|
|
The output will look something like:
|
|
.Bd -unfilled -offset indent
|
|
Components:
|
|
/dev/sd1e: optimal
|
|
/dev/sd2e: optimal
|
|
/dev/sd3e: optimal
|
|
Spares:
|
|
/dev/sd4e: spare
|
|
.Ed
|
|
.Pp
|
|
This indicates that all is well with the RAID set.
|
|
.Pp
|
|
To check the component label of /dev/sd1e, the following is used:
|
|
.Bd -unfilled -offset indent
|
|
raidctl -g /dev/sd1e raid0
|
|
.Ed
|
|
.Pp
|
|
The output of this command will look something like:
|
|
.Bd -unfilled -offset indent
|
|
Component label for /dev/sd2e:
|
|
Version: 1
|
|
Serial Number: 112341
|
|
Mod counter: 6
|
|
Row: 0
|
|
Column: 1
|
|
Num Rows: 1
|
|
Num Columns: 3
|
|
Clean: 0
|
|
Status: optimal
|
|
.Ed
|
|
.Pp
|
|
For a component label to be considered valid, that particular
|
|
component label must be in agreement with the other component labels
|
|
in the set. For example, the serial number, 'modification counter',
|
|
number of rows and number of columns must all be in agreement. If any
|
|
of these are different, then the component is not considered to be
|
|
part of the set.
|
|
.Pp
|
|
If for some reason
|
|
(perhaps to test reconstruction) it is necessary to pretend a drive
|
|
has failed, the following will perform that function:
|
|
.Bd -unfilled -offset indent
|
|
raidctl -f /dev/sd2e raid0
|
|
.Ed
|
|
.Pp
|
|
The system will then be performing all operations in degraded mode,
|
|
were missing data is re-computed from existing data and the parity.
|
|
In this case, obtaining the status of raid0 will return:
|
|
.Bd -unfilled -offset indent
|
|
Components:
|
|
/dev/sd1e: optimal
|
|
/dev/sd2e: failed
|
|
/dev/sd3e: optimal
|
|
Spares:
|
|
/dev/sd4e: spare
|
|
.Ed
|
|
.Pp
|
|
Note that with the use of
|
|
.Fl f
|
|
a reconstruction has not been started. To both fail the disk and
|
|
start a reconstruction, the
|
|
.Fl F
|
|
option must be used:
|
|
.Bd -unfilled -offset indent
|
|
raidctl -F /dev/sd2e raid0
|
|
.Ed
|
|
.Pp
|
|
The
|
|
.Fl f
|
|
option may be used first, and then the
|
|
.Fl F
|
|
option used later, on the same disk, if desired.
|
|
Immediately after the reconstruction is started, the status will report:
|
|
.Bd -unfilled -offset indent
|
|
Components:
|
|
/dev/sd1e: optimal
|
|
/dev/sd2e: reconstructing
|
|
/dev/sd3e: optimal
|
|
Spares:
|
|
/dev/sd4e: used_spare
|
|
.Ed
|
|
.Pp
|
|
This indicates that a reconstruction is in progress. To find out how
|
|
the reconstruction is progressing the
|
|
.Fl S
|
|
option may be used. This will indicate the progress in terms of the
|
|
percentage of the reconstruction that is completed. When the
|
|
reconstruction is finished the
|
|
.Fl s
|
|
option will show:
|
|
.Bd -unfilled -offset indent
|
|
Components:
|
|
/dev/sd1e: optimal
|
|
/dev/sd2e: spared
|
|
/dev/sd3e: optimal
|
|
Spares:
|
|
/dev/sd4e: used_spare
|
|
.Ed
|
|
.Pp
|
|
At this point there are at least two options. First, if /dev/sd2e is
|
|
known to be good (i.e. the failure was either caused by
|
|
.Fl f
|
|
or
|
|
.Fl F ,
|
|
or the failed disk was replaced), then a copyback of the data can
|
|
be initiated with the
|
|
.Fl B
|
|
option. In this example, this would copy the entire contents of
|
|
/dev/sd4e to /dev/sd2e. Once the copyback procedure is complete, the
|
|
status of the device would be:
|
|
.Bd -unfilled -offset indent
|
|
Components:
|
|
/dev/sd1e: optimal
|
|
/dev/sd2e: optimal
|
|
/dev/sd3e: optimal
|
|
Spares:
|
|
/dev/sd4e: spare
|
|
.Ed
|
|
.Pp
|
|
and the system is back to normal operation.
|
|
.Pp
|
|
The second option after the reconstruction is to simply use /dev/sd4e
|
|
in place of /dev/sd2e in the configuration file. For example, the
|
|
configuration file (in part) might now look like:
|
|
.Bd -unfilled -offset indent
|
|
START array
|
|
1 3 0
|
|
|
|
START drives
|
|
/dev/sd1e
|
|
/dev/sd4e
|
|
/dev/sd3e
|
|
.Ed
|
|
.Pp
|
|
This can be done as /dev/sd4e is completely interchangeable with
|
|
/dev/sd2e at this point. Note that extreme care must be taken when
|
|
changing the order of the drives in a configuration. This is one of
|
|
the few instances where the devices and/or their orderings can be
|
|
changed without loss of data! In general, the ordering of components
|
|
in a configuration file should
|
|
.Ar never
|
|
be changed.
|
|
.Pp
|
|
If a component fails and there are no hot spares
|
|
available on-line, the status of the RAID set might look like:
|
|
.Bd -unfilled -offset indent
|
|
Components:
|
|
/dev/sd1e: optimal
|
|
/dev/sd2e: failed
|
|
/dev/sd3e: optimal
|
|
No spares.
|
|
.Ed
|
|
.Pp
|
|
In this case there are a number of options. The first option is to add a hot
|
|
spare using:
|
|
.Bd -unfilled -offset indent
|
|
raidctl -a /dev/sd4e raid0
|
|
.Ed
|
|
.Pp
|
|
After the hot add, the status would then be:
|
|
.Bd -unfilled -offset indent
|
|
Components:
|
|
/dev/sd1e: optimal
|
|
/dev/sd2e: failed
|
|
/dev/sd3e: optimal
|
|
Spares:
|
|
/dev/sd4e: spare
|
|
.Ed
|
|
.Pp
|
|
Reconstruction could then take place using
|
|
.Fl F
|
|
as describe above.
|
|
.Pp
|
|
A second option is to rebuild directly onto /dev/sd2e. Once the disk
|
|
containing /dev/sd2e has been replaced, one can simply use:
|
|
.Bd -unfilled -offset indent
|
|
raidctl -R /dev/sd2e raid0
|
|
.Ed
|
|
.Pp
|
|
to rebuild the /dev/sd2e component. As the rebuilding is in progress,
|
|
the status will be:
|
|
.Bd -unfilled -offset indent
|
|
Components:
|
|
/dev/sd1e: optimal
|
|
/dev/sd2e: reconstructing
|
|
/dev/sd3e: optimal
|
|
No spares.
|
|
.Ed
|
|
.Pp
|
|
and when completed, will be:
|
|
.Bd -unfilled -offset indent
|
|
Components:
|
|
/dev/sd1e: optimal
|
|
/dev/sd2e: optimal
|
|
/dev/sd3e: optimal
|
|
No spares.
|
|
.Ed
|
|
.Pp
|
|
|
|
.Pp
|
|
The final operation performed by
|
|
.Nm
|
|
is to unconfigure a
|
|
.Xr raid 4
|
|
device. This is accomplished via a simple:
|
|
.Bd -unfilled -offset indent
|
|
raidctl -u raid0
|
|
.Ed
|
|
.Pp
|
|
at which point the device is ready to be reconfigured.
|
|
.Sh WARNINGS
|
|
Certain RAID levels (1, 4, 5, 6, and others) can protect against some
|
|
data loss due to component failure. However the loss of two
|
|
components of a RAID 4 or 5 system, or the loss of a single component
|
|
of a RAID 0 system will result in the entire filesystem being lost.
|
|
RAID is
|
|
.Ar NOT
|
|
a substitute for good backup practices.
|
|
.Pp
|
|
Recomputation of parity
|
|
.Ar MUST
|
|
be performed whenever there is a chance that it may have been
|
|
compromised. This includes after system crashes, or before a RAID
|
|
device has been used for the first time. Failure to keep parity
|
|
correct will be catastrophic should a component ever fail -- it is
|
|
better to use RAID 0 and get the additional space and speed, than it
|
|
is to use parity, but not keep the parity correct. At least with RAID
|
|
0 there is no perception of increased data security.
|
|
.Pp
|
|
.Sh FILES
|
|
.Bl -tag -width /dev/XXrXraidX -compact
|
|
.It Pa /dev/{,r}raid*
|
|
.Cm raid
|
|
device special files.
|
|
.El
|
|
.Pp
|
|
.Sh SEE ALSO
|
|
.Xr raid 4 ,
|
|
.Xr ccd 4 ,
|
|
.Xr rc 8
|
|
.Sh BUGS
|
|
Hot-spare removal is currently not available.
|
|
.Sh HISTORY
|
|
RAIDframe is a framework for rapid prototyping of RAID structures
|
|
developed by the folks at the Parallel Data Laboratory at Carnegie
|
|
Mellon University (CMU).
|
|
A more complete description of the internals and functionality of
|
|
RAIDframe is found in the paper "RAIDframe: A Rapid Prototyping Tool
|
|
for RAID Systems", by William V. Courtright II, Garth Gibson, Mark
|
|
Holland, LeAnn Neal Reilly, and Jim Zelenka, and published by the
|
|
Parallel Data Laboratory of Carnegie Mellon University.
|
|
.Pp
|
|
The
|
|
.Nm
|
|
command first appeared as a program in CMU's RAIDframe v1.1 distribution. This
|
|
version of
|
|
.Nm
|
|
is a complete re-write, and first appeared in
|
|
.Nx 1.4 .
|
|
.Sh COPYRIGHT
|
|
.Bd -unfilled
|
|
|
|
The RAIDframe Copyright is as follows:
|
|
|
|
Copyright (c) 1994-1996 Carnegie-Mellon University.
|
|
All rights reserved.
|
|
|
|
Permission to use, copy, modify and distribute this software and
|
|
its documentation is hereby granted, provided that both the copyright
|
|
notice and this permission notice appear in all copies of the
|
|
software, derivative works or modified versions, and any portions
|
|
thereof, and that both notices appear in supporting documentation.
|
|
|
|
CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
|
|
CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
|
|
FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
|
|
|
|
Carnegie Mellon requests users of this software to return to
|
|
|
|
Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
|
|
School of Computer Science
|
|
Carnegie Mellon University
|
|
Pittsburgh PA 15213-3890
|
|
|
|
any improvements or extensions that they make and grant Carnegie the
|
|
rights to redistribute these changes.
|
|
|
|
.Ed
|