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metadetach


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.
     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
     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 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 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  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 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 command to perform its  administrative
         function  within  the  specified  diskset.  Without this
         option, the command performs its function on local meta-
         devices.


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 giga-
         bytes, T or t for terabytes, and B or b for blocks (sec-
         tors).  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
     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  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

     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/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.
     Afterwards,  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 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.


ATTRIBUTES
     See attributes(5) for descriptions of the  following  attri-
     butes:



     ____________________________________________________________
    |       ATTRIBUTE TYPE        |       ATTRIBUTE VALUE       |
    |_____________________________|_____________________________|
    | Availability                | SUNWmdu                     |
    |_____________________________|_____________________________|


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)

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 mount_ufs(1M) for more
     information about UFS logging.










Man pages from Solaris 10 Update 8. See docs.sun.com and www.oracle.com for further documentation and Solaris information.
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