metattach(1M) 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 ser‐
vice. 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 ker‐
nel. 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 ker‐
nel, the large volumes are visible through metastat output. Large vol‐
umes 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 ver‐
sion of the Solaris Operating System.
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 metadevice is attached to a mirror,
metattach automatically starts a resync operation to the new submirror.
metadetach detaches submirrors from mirrors and logging devices 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
mount_ufs(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 Detach‐
ing 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 important 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. In this
case, use a value from the hardware configuration as the value for
the alignment. When using this option in conjunction with a soft‐
ware 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 performance.
-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 uppercase 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 /dev/dsk/c0t0d0s2, being added to the concatenation,
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 metadevice.
size | all
The amount of space to add to the soft partition 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 mir‐
ror.
trans
The metadevice name of the trans metadevice (not the master or log‐
ging device).
EXAMPLES
Example 1 Concatenating a New Slice to a Metadevice
This example concatenates a single new slice to an existing metadevice,
d8. Afterwards, you would use the growfs(1M) command to expand the file
system.
# metattach d8 /dev/dsk/c0t1d0s2
Example 2 Detaching Logging Device from Trans Metadevice
This example detaches the logging device from a trans metadevice d9.
Notice that you do not have to specify the logging 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 calcu‐
lations, so it is protected against single-device failure.
Example 4 Expanding a Soft Partition
The following example expands a soft partition, d42, attaching all
space available on the underlying device.
# metattach d42 all
When you add additional space to a soft partition, the additional space
is taken from any available space on the slice and might not be con‐
tiguous with the existing soft partition.
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/dsk/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. After‐
wards, you would use the growfs(1M) command to expand 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 partition 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.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
┌─────────────────────────────┬─────────────────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├─────────────────────────────┼─────────────────────────────┤
│Availability │SUNWmdu │
└─────────────────────────────┴─────────────────────────────┘
SEE ALSOmdmonitord(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), metas‐
sist(1M), metastat(1M), metasync(1M), md.tab(4), md.cf(4), mddb.cf(4),
md.tab(4), attributes(5), md(7D)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 metade‐
vice might not be the same as the data that existed on the mirror prior
to running metadetach. In particular, 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. Existing trans
devices are not logging. They pass data directly through to the under‐
lying device. See mount_ufs(1M) for more information about UFS logging.
SunOS 5.10 8 Feb 2007 metattach(1M)
