System Administration Commands metattach(1M)
NAME
metattach, metadetach - attach or detach a metadevice
SYNOPSIS
/usr/sbin/metattach [-h]
/usr/sbin/metattach [-s setname] mirror [metadevice]
/usr/sbin/metattach [-s setname] [-i interlace] concat/stripe component...
/usr/sbin/metattach [-s setname] RAID component...
/usr/sbin/metattach [-s setname] [-A alignment] softpart size all
/usr/sbin/metadetach [-s setname] [-f] mirror submirror
/usr/sbin/metadetach [-s setname] [-f] trans
DESCRIPTION
metattach adds submirrors to a mirror, grows metadevices, or
grows soft partitions. Growing metadevices can be done
without interrupting service. To grow the size of a mirror
or trans, the slices must be added to the submirrors or to
the master devices.
Solaris Volume Manager supports storage devices and logical
volumes greater than 1 terabyte (TB) when a system runs a
64-bit Solaris kernel. Support for large volumes is
automatic. If a device greater than 1 TB is created, Solaris
Volume Manager configures it appropriately and without user
intervention.
If a system with large volumes is rebooted under a 32-bit
Solaris kernel, the large volumes are visible through metas-
tat output. Large volumes cannot be accessed, modified or
deleted, and no new large volumes can be created. Any
volumes or file systems on a large volume in this situation
are also unavailable. If a system with large volumes is
rebooted under a version of Solaris prior to the Solaris 9
4/03 release, Solaris Volume Manager does not start. You
must remove all large volumes before Solaris Volume Manager
runs under an earlier version of the Solaris Operating Sys-
tem.
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System Administration Commands metattach(1M)
Solaris Volume Manager supports one-to-four-way mirrors. You
can only attach a metadevice to a mirror if there are three
or fewer submirrors beneath the mirror. Once a new metadev-
ice is attached to a mirror, metattach automatically starts
a resync operation to the new submirror.
metadetach detaches submirrors from mirrors and logging dev-
ices from trans metadevices.
When a submirror is detached from a mirror, it is no longer
part of the mirror, thus reads and writes to and from that
metadevice by way of the mirror are no longer performed
through the mirror. Detaching the only existing submirror is
not allowed. Detaching a submirror that has slices reported
as needing maintenance (by metastat) is not allowed unless
the -f (force) flag is used.
metadetach also detaches the logging device from a trans.
This step is necessary before you can clear the trans
volume. Trans metadevices have been replaced by UFS logging.
Existing trans devices are not logging. They pass data
directly through to the underlying device. See mountufs(1M)
for more information about UFS logging.
Detaching the logging device from a busy trans device is not
allowed unless the -f (force) flag is used. Even so, the
logging device is not actually detached until the trans is
idle. The trans is in the Detaching state (metastat) until
the logging device is detached.
OPTIONS
Root privileges are required for all of the following
options except -h.
The following options are supported:
-A alignment Set the value of the soft partition extent
alignment. Use this option when it is impor-
tant specify a starting offset for the soft
partition. It preserves the data alignment
between the metadevice address space and the
address space of the underlying physical
device.
For example, a hardware device that does
checksumming should not have its I/O
requests divided by Solaris Volume Manager.
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System Administration Commands metattach(1M)
In this case, use a value from the hardware
configuration as the value for the align-
ment. When using this option in conjunction
with a software I/O load, the alignment
value corresponds to the I/O load of the
application. This prevents I/O from being
divided unnecessarily and affecting perfor-
mance.
-f Force the detaching of metadevices that have
components that need maintenance or are
busy. You can use this option only when a
mirror is in a maintenance state that can be
fixed with metareplace(1M). If the mirror is
in a maintenance state that can only be
fixed with metasync(1M) (as shown by the
output of metastat(1M)), metadetach -f has
no effect, because the mirrors must be
resynchronized before one of them can be
detached.
-h Display a usage message.
-i interlace Specify the interlace value for stripes,
where size is a specified value followed by
either k for kilobytes, m for megabytes, or
b for blocks. The units can be either upper-
case or lowercase. If size is not specified,
the size defaults to the interlace size of
the last stripe of the metadevice. When an
interlace size change is made on a stripe,
it is carried forward on all stripes that
follow.
-s setname Specify the name of the diskset on which the
metattach command or the metadetach command
works.. Using the -s option causes the com-
mand to perform its administrative function
within the specified diskset. Without this
option, the command performs its function on
local metadevices.
OPERANDS
The following operands are supported:
component The logical name for the physical slice
(partition) on a disk drive, such as
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/dev/dsk/c0t0d0s2, being added to the con-
catenation, stripe, concatenation of
stripes, or RAID5 metadevice.
concat/stripe The metadevice name of the concatenation,
stripe, or concatenation of stripes.
log The metadevice name of the logging device
to be attached to the trans metadevice.
metadevice The metadevice name to be attached to the
mirror as a submirror. This metadevice must
have been previously created by the
metainit command.
mirror The name of the mirror.
RAID The metadevice name of the RAID5 metadev-
ice.
size all The amount of space to add to the soft par-
tition in K or k for kilobytes, M or m for
megabytes, G or g for gigabytes, T or t for
terabytes, and B or b for blocks (sectors).
All values represent powers of 2, and upper
and lower case options are equivalent. Only
integer values are permitted. The literal
all specifies that the soft partition
should grow to occupy all available space
on the underlying volume.
softpart The metadevice name of the existing soft
partition.
submirror The metadevice name of the submirror to be
detached from the mirror.
trans The metadevice name of the trans metadevice
(not the master or logging device).
EXAMPLES
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System Administration Commands metattach(1M)
Example 1 Concatenating a New Slice to a Metadevice
This example concatenates a single new slice to an existing
metadevice, Volume.1. Afterwards, you would use the
growfs(1M) command to expand the file system.
# metattach Volume.1 /dev/dsk/c0t1d0s2
Example 2 Detaching Logging Device from Trans Metadevice
This example detaches the logging device from a trans meta-
device d9. Notice that you do not have to specify the log-
ging device itself, as there can only be one.
# metadetach d9
Example 3 Expanding a RAID5 Metadevice
This example expands a RAID5 metadevice, d45, by attaching
another slice.
# metattach d45 /dev/dsk/c3t0d0s2
When you add additional slices to a RAID5 metadevice, the
additional space is devoted to data. No new parity blocks
are allocated. The data on the added slices is, however,
included in the overall parity calculations, so it is pro-
tected against single-device failure.
Example 4 Expanding a Soft Partition
The following example expands a soft partition, d42, attach-
ing all space available on the underlying device.
# metattach d42 all
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System Administration Commands metattach(1M)
When you add additional space to a soft partition, the addi-
tional space is taken from any available space on the slice
and might not be contiguous with the existing soft parti-
tion.
Example 5 Adding Space to Two-Way Mirror
This example adds space to a two-way mirror by adding a
slice to each submirror. Afterwards, you would use the
growfs(1M) command to expand the file system.
# metattach d9 /dev/dsk/c0t2d0s5
# metattach d10 /dev/dsk/c0t3d0s5
This example tells the mirror to grow to the size of the
underlying devices
# metattach d11
This example increases the size of the UFS on the device so
the space can be used.
# growfs -M /export /dev/md/rdsk/d11
Example 6 Detaching a Submirror from a Mirror
This example detaches a submirror, d2, from a mirror, d4.
# metadetach d4 d2
Example 7 Adding Four Slices to Metadevice
This example adds four slices to an existing metadevice, d9.
Afterwards, you would use the growfs(1M) command to expand
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System Administration Commands metattach(1M)
the file system.
# metattach d9 /dev/dsk/c0t1d0s2 /dev/dsk/c0t2d0s2 /dev/dsk/c0t3d0s2 /dev/dsk/c0t4d0s2
Example 8 Setting the Value of the Soft Partition Extent
Alignment
This example shows how to set the alignment of the soft par-
tition to 1mb when the soft partition is expanded.
# metattach -s red -A 2m d13 1m
EXIT STATUS
The following exit values are returned:
0 Successful completion.
>0 An error occurred.
ATRIBUTES
See attributes(5) for descriptions of the following attri-
butes:
ATRIBUTE TYPE ATRIBUTE VALUE
Availability SUNWmdu
Interface Stability Stable
SEE ALSO
mdmonitord(1M), metaclear(1M), metadb(1M), metahs(1M),
metainit(1M), metaoffline(1M), metaonline(1M),
metaparam(1M), metarecover(1M), metarename(1M),
metareplace(1M), metaroot(1M), metaset(1M), metassist(1M),
metastat(1M), metasync(1M), md.tab(4), md.cf(4), mddb.cf(4),
md.tab(4), attributes(5), md(7D)
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System Administration Commands metattach(1M)
WARNINGS
This section provides information regarding warnings for
devices greater than 1 TB and for multi-way mirrors.
Devices and Volumes Greater Than 1 TB
Do not create large (>1 TB) volumes if you expect to run the
Solaris Operating System with a 32-bit kernel or if you
expect to use a version of the Solaris Operating System
prior to Solaris 9 4/03.
Multi-Way Mirrors
When a submirror is detached from its mirror, the data on
the metadevice might not be the same as the data that
existed on the mirror prior to running metadetach. In par-
ticular, if the -f option was needed, the metadevice and
mirror probably do not contain the same data.
NOTES
Trans metadevices have been replaced by UFS logging. Exist-
ing trans devices are not logging. They pass data directly
through to the underlying device. See mountufs(1M) for more
information about UFS logging.
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