Add a few more examples, and a summary.
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oster
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.\" $NetBSD: raidctl.8,v 1.15 2000/02/25 22:38:51 oster Exp $
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.\" $NetBSD: raidctl.8,v 1.16 2000/02/26 04:02:03 oster Exp $
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.\"
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.\" Copyright (c) 1998 The NetBSD Foundation, Inc.
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.\" All rights reserved.
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@ -478,15 +478,62 @@ START queue
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fifo 100
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.Ed
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.Pp
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is created in a file. In this example, the above configuration
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will be in a filed called
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.Sq raid0.conf .
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The above configuration file specifies a RAID
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5 set consisting of the components /dev/sd1e,
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/dev/sd2e, and /dev/sd3e, with /dev/sd4e available as a
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is created in a file. The above configuration file specifies a RAID 5
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set consisting of the components /dev/sd1e, /dev/sd2e, and /dev/sd3e,
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with /dev/sd4e available as a
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.Sq hot spare
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in case one of
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the three main drives should fail.
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the three main drives should fail. A RAID 0 set would be specified in
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a similar way:
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.Bd -unfilled -offset indent
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START array
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# numRow numCol numSpare
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1 4 0
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START disks
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/dev/sd10e
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/dev/sd11e
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/dev/sd12e
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/dev/sd13e
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START layout
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# sectPerSU SUsPerParityUnit SUsPerReconUnit RAID_level_0
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64 1 1 0
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START queue
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fifo 100
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.Ed
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.Pp
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In this case, devices /dev/sd10e, /dev/sd11e, /dev/sd12e, and /dev/sd13e
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are the components that make up this RAID set. Note that there are no
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hot spares for a RAID 0 set, since there is no way to recover data if
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any of the components fail.
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.Pp
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For a RAID 1 (mirror) set, the following configuration might be used:
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.Bd -unfilled -offset indent
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START array
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# numRow numCol numSpare
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1 2 0
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START disks
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/dev/sd20e
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/dev/sd21e
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START layout
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# sectPerSU SUsPerParityUnit SUsPerReconUnit RAID_level_1
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128 1 1 1
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START queue
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fifo 100
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.Ed
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.Pp
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In this case, /dev/sd20e and /dev/sd21e are the two components of the
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mirror set. While no hot spares have been specified in this
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configuration, they easily could be, just as they were specified in
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the RAID 5 case above. Note as well that RAID 1 sets are currently
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limited to only 2 components. At present, n-way mirroring is not
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possible.
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.Pp
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The first time a RAID set is configured, the
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.Fl C
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option must be used:
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@ -494,15 +541,19 @@ option must be used:
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raidctl -C raid0.conf raid0
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.Ed
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.Pp
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The
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where
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.Sq raid0.conf
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is the name of the RAID configuration file. The
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.Fl C
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forces the configuration to succeed, even if any of the component
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labels are incorrect. This option should not be used lightly in
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labels are incorrect. The
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.Fl C
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option should not be used lightly in
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situations other than initial configurations, as if
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the system is refusing to configure a RAID set, there is probably a
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very good reason for it. After the initial configuration is done (and
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appropriate component labels are added with the
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.Ar I
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.Fl I
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option) then raid0 can be configured normally with:
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.Bd -unfilled -offset indent
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raidctl -c raid0.conf raid0
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@ -517,24 +568,30 @@ raidctl -I 112341 raid0
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.Pp
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where
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.Sq 112341
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is a user-specified serial number for the RAID set. Using different
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is a user-specified serial number for the RAID set. This
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initialization step is
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.Ar required
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for all RAID sets. As well, using different
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serial numbers between RAID sets is
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.Ar strongly encouraged ,
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as using the
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same serial number for all RAID sets will only serve to decrease the
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usefulness of the component label checking.
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as using the same serial number for all RAID sets will only serve to
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decrease the usefulness of the component label checking.
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.Pp
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Initializing the RAID set is done via:
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.Bd -unfilled -offset indent
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raidctl -i raid0
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.Ed
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.Pp
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This initialization includes ensuring that the parity (if any) on the
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RAID set is correct. Since this initialization may be quite
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time-consuming, the
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.Ar v
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This initialization
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.Ar MUST
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be done for
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.Ar all
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RAID sets, since among other things it verifies that the parity (if
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any) on the RAID set is correct. Since this initialization may be
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quite time-consuming, the
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.Fl v
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option may be also used in conjunction with
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.Ar i .
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.Fl i .
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This will give more verbose output on the
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status of the initialization:
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.Bd -unfilled -offset indent
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@ -869,6 +926,78 @@ raidctl -u raid0
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.Ed
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.Pp
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at which point the device is ready to be reconfigured.
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.Pp
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.Ss Summary
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Despite the length of this man-page, configuring a RAID set is a
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relatively straight-forward process. All that needs to be done is the
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following steps:
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.Bl -enum
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.It
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Use
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.Xr disklabel 8
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to create the components (of type RAID).
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.It
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Construct a RAID configuration file: e.g.
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.Sq raid0.conf
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.It
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Configure the RAID set with:
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.Bd -unfilled -offset indent
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raidctl -C raid0.conf raid0
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.Ed
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.Pp
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.It
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Initialize the component labels with:
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.Bd -unfilled -offset indent
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raidctl -I 123456 raid0
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.Ed
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.Pp
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.It
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Initialize other important parts of the set with:
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.Bd -unfilled -offset indent
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raidctl -i raid0
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.Ed
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.Pp
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.It
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Get the default label for the RAID set:
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.Bd -unfilled -offset indent
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disklabel raid0 > /tmp/label
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.Ed
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.Pp
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.It
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Edit the label:
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.Bd -unfilled -offset indent
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vi /tmp/label
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.Ed
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.Pp
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.It
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Put the new label on the RAID set:
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.Bd -unfilled -offset indent
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disklabel -R -r raid0 /tmp/label
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.Ed
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.Pp
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.It
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Create the filesystem:
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.Bd -unfilled -offset indent
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newfs /dev/rraid0e
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.Ed
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.Pp
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.It
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Mount the filesystem:
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.Bd -unfilled -offset indent
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mount /dev/raid0e /mnt
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.Ed
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.Pp
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.It
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Use:
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.Bd -unfilled -offset indent
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raidctl -c raid0.conf raid0
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.Ed
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.Pp
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To re-configure the RAID set the next time it is needed, or put
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raid0.conf into /etc where it will automatically be started by
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the /etc/rc scripts.
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.El
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.Pp
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.Sh WARNINGS
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Certain RAID levels (1, 4, 5, 6, and others) can protect against some
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data loss due to component failure. However the loss of two
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