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metaset


NAME
     metaset - configure disk sets

SYNOPSIS
     /usr/sbin/metaset  -s setname [-M-a -h hostname]


     /usr/sbin/metaset  -s setname -A{enable | disable}


     /usr/sbin/metaset  -s setname [-A{enable | disable}]
      -a -h hostname...


     /usr/sbin/metaset  -s setname -a [-l length] [-L] drivename...


     /usr/sbin/metaset  -s setname -C {take | release |
      purge}


     /usr/sbin/metaset  -s setname -d [-f] -h hostname...


     /usr/sbin/metaset  -s setname -d [-f] drivename...


     /usr/sbin/metaset  -s setname -j


     /usr/sbin/metaset  -s setname -r


     /usr/sbin/metaset  -s setname -w


     /usr/sbin/metaset  -s setname -t [-f] [-u tagnumber]
      [y]


     /usr/sbin/metaset  -s setname -b


     /usr/sbin/metaset  -s setname -P


     /usr/sbin/metaset  -s setname -q


     /usr/sbin/metaset  -s setname -o [-h hostname]


     /usr/sbin/metaset  [-s setname]


     /usr/sbin/metaset  [-s setname] -a | -d [ [m] mediator_host_list]


DESCRIPTION
     The metaset command administers sets of disks in named  disk
     sets.  Named  disk  sets include any disk set that is not in
     the local set. While disk sets  enable  a  high-availability
     configuration,  Solaris Volume Manager itself does not actu-
     ally provide a high-availability environment.


     A single-owner disk set configuration manages storage  on  a
     SAN  or  fabric-attached storage, or provides namespace con-
     trol and state database replica management for  a  specified
     set of disks.


     In a shared disk set configuration, multiple hosts are  phy-
     sically  connected  to  the same set of disks. When one host
     fails, another host has exclusive access to the disks.  Each
     host  can  control  a shared disk set, but only one host can
     control it at a time.


     When you add a new disk to  any  disk  set,  Solaris  Volume
     Manager  checks  the  disk format. If necessary, it reparti-
     tions the disk to ensure that the disk has an  appropriately
     configured  reserved  slice 7 (or slice 6 on an EFI labelled
     device) with adequate space for a  state  database  replica.
     The  precise  size of slice 7 (or slice 6 on an EFI labelled
     device) depends on the disk geometry.  For  tradtional  disk
     sets,  the  slice  is  no  less  than 4 Mbytes, and probably
     closer to 6 Mbytes, depending on where  the  cylinder  boun-
     daries  lie.  For  multi-owner  disk  sets,  the  slice is a
     minimum of 256 Mbytes. The minimal size for  slice  7  might
     change  in  the future. This change is based on a variety of
     factors, including the size of the  state  database  replica
     and information to be stored in the state database replica.


     For use in disk sets, disks must have a dedicated slice (six
     or seven) that meets specific criteria:

         o    The slice must start at sector 0

         o    The slice must include enough space for disk label

         o    The state database replicas cannot be mounted

         o    The slice does not overlap with any  other  slices,
              including slice 2


     If the existing partition table does  not  meet  these  cri-
     teria,  or  if  the  -L  flag  is  specified, Solaris Volume
     Manager repartitions the disk. A small portion of each drive
     is  reserved  in slice 7 (or slice 6 on an EFI labelled dev-
     ice) for use by Solaris Volume Manager. The remainder of the
     space  on  each  drive  is placed into slice 0. Any existing
     data on the disks is lost by repartitioning.


     After you add a drive to a disk set, it can be repartitioned
     as necessary, with the exception that slice 7 (or slice 6 on
     an EFI labelled device) is not altered in any way.


     After a disk set is  created  and  metadevices  are  set  up
     within  the  set,  the  metadevice  name is in the following
     form:


     /dev/md/setname/{dsk,rdsk}/dnumber


     where setname is the name of the disk set, and number is the
     number of the metadevice (0-127).


     If you have disk sets that you upgraded from Solstice  Disk-
     Suite  software,  the default state database replica size on
     those sets is 1034 blocks, not  the  8192  block  size  from
     Solaris Volume Manager. Also, slice 7 on the disks that were
     added under Solstice DiskSuite are  correspondingly  smaller
     than  slice  7 on disks that were added under Solaris Volume
     Manager.


     If disks you add to a disk  set  have  acceptable  slice  7s
     (that start at cylinder 0 and that have sufficient space for
     the state database replica), they are not reformatted.


     Hot spare pools within local disk sets use standard  Solaris
     Volume  Manager  naming  conventions.  Hot  spare pools with
     shared disk sets use the following convention:


     setname/hspnumber


     where setname is the name of the disk set, and number is the
     number of the hot spare pool (0-999).

  Multi-node Environment
     To create and work with a disk set in a multi-node  environ-
     ment, root must be a member of Group 14 on all hosts, or the
     /.rhosts file must contain  an  entry  for  all  other  host
     names. This is not required in a SunCluster 3.x enviroment.

  Tagged data
     Tagged data occurs when there are different  versions  of  a
     disk  set's  replicas.  This tagged data consists of the set
     owner's nodename, the hardware serial number  of  the  owner
     and  the  time it was written out to the available replicas.
     The system administer can use this information to  determine
     which replica contains the correct data.


     When a disk set is configured with an even number of storage
     enclosures  and has replicas balanced across them evenly, it
     is possible that up to half of the replicas can be lost (for
     example,  through  a  power  failure  of half of the storage
     enclosures). After the enclosure that went down is rebooted,
     half of the replicas are not recognized by SVM. When the set
     is retaken, the metaset command returns an error  of  "stale
     databases",  and  all  of the metadevices are in a read-only
     state.


     Some of the replicas that are  not  recognized  need  to  be
     deleted.  The  action  of  deleting the replicas also causes
     updates to the replicas that are not  being  deleted.  In  a
     dual hosted disk set environment, the second node can access
     the deleted replicas instead of the existing  replicas  when
     it  takes  the set. This leads to the possibility of getting
     the wrong replica record on a disk set take. An  error  mes-
     sage is displayed, and user intervention is required.


     Use the -q to query the disk set and the  -t,  -u,  and  -y,
     options  to  select  the  tag  and  take  the  disk set. See
     OPTIONS.

  Mediator Configuration
     SVM provides support for a low-end HA solution consisting of
     two  hosts  that share only two strings of drives. The hosts
     in this type of configuration, referred to as  mediators  or
     mediator  hosts, run a special daemon, rpc.metamedd(1M). The
     mediator hosts take on additional responsibilities to ensure
     that  data  is  available  in  the  case  of  host  or drive
     failures.

     A mediator configuration can survive the failure of a single
     host  or  a  single string of drives, without administrative
     intervention. If both a host and a  string  of  drives  fail
     (multiple  failures),  the  integrity  of the data cannot be
     guaranteed. At this point,  administrative  intervention  is
     required  to  make the data accessible. See mediator(7D) for
     further details.


     Use the -m option to add or  delete  a  mediator  host.  See
     OPTIONS.

OPTIONS
     The following options are supported:

     -a

         Add drives or hosts to the named set. For a drive to  be
         accepted into a set, the drive must not be in use within
         another metadevice or disk set, mounted on,  or  swapped
         on.  When  the  drive  is  accepted  into the set, it is
         repartitioned and the metadevice state database  replica
         (for the set) can be placed on it. However, if a slice 7
         (or slice 6  on  an  EFI  labelled  device),  starts  at
         cylinder 0, and is large enough to hold a state database
         replica, then the disk is not repartioned. Also, a drive
         is  not  accepted  if  it  cannot  be found on all hosts
         specified as part of the set. This means that if a  host
         within  the  specified set is unreachable due to network
         problems, or is administratively down, the add fails.


     -a | -d | -m mediator_host_list

         Add (-a) or delete (-d) mediator hosts to the  specified
         disk set. A mediator_host_list is the nodename(4) of the
         mediator host to be added and (for  adding)  up  to  two
         other  aliases  for  the mediator host. The nodename and
         aliases for each mediator host  are  separated  only  by
         commas.  Up to three mediator hosts can be specified for
         the named disk set. Specify only the  nodename  of  that
         host as the argument to -m to delete a mediator host.

         In a single metaset command you can add or delete  three
         mediator hosts. See EXAMPLES.


     -A {enable | disable}

         Specify auto-take status for a disk set. If auto-take is
         enabled  for  a set, the disk set is automatically taken
         at boot, and file systems on volumes within the disk set
         can  be mounted through /etc/vfstab entries. Only a sin-
         gle host can be associated with  an  auto-take  set,  so
         attempts  to  add  a  second host to an auto-take set or
         attempts to configure a disk set with multiple hosts  as
         auto-take  fails  with an error message. Disabling auto-
         take status for a specific disk set causes the disk  set
         to  revert  to normal behavior. That is, the disk set is
         potentially shared (non-concurrently) among  hosts,  and
         unavailable for mounting through /etc/vfstab.


     -b

         Insure that the replicas are  distributed  according  to
         the replica layout algorithm. This can be invoked at any
         time, and does nothing if  the  replicas  are  correctly
         distributed. In cases where the user has used the metadb
         command to manually remove or add replicas, this command
         can  be used to insure that the distribution of replicas
         matches the replica layout algorithm.


     -C {take | release | purge}

         Do not interact with the Cluster Framework when used  in
         a  Sun  Cluster  3 environment. In effect, this means do
         not modify the Cluster Configuration  Repository.  These
         options  should  only  be  used to fix a broken disk set
         configuration. This option is not for use with a  multi-
         owner disk set.

         take

             Take ownership of the disk set but do not inform the
             Cluster Framework that the disk set is available


         release

             Release ownership of the disk set without  informing
             the  Cluster  Framework.  This option should only be
             used if the disk set ownership was  taken  with  the
             corresponding -C take option.


         purge

             Remove the disk set without  informing  the  Cluster
             Framework that the disk set has been purged



     -d

         Delete drives or hosts from the named disk  set.  For  a
         drive  to  be  deleted, it must not be in use within the
         set. The last host cannot be deleted unless all  of  the
         drives  within  the  set  are deleted. Deleting the last
         host in a disk set destroys the disk set.

         This option fails on a multi-owner disk set if  attempt-
         ing to withdraw the master node while other nodes are in
         the set.


     -f

         Force one of three actions to occur: takes ownership  of
         a  disk  set  when  used  with -t; deletes the last disk
         drive from the disk set; or deletes the last  host  from
         the  disk  set.  Deleting  the last drive or host from a
         disk set requires the -d option.

         When used to forcibly take ownership of  the  disk  set,
         this  causes  the  disk set to be grabbed whether or not
         another host owns the set. All of the disks  within  the
         set  are taken over (reserved) and fail fast is enabled,
         causing the other host to panic if it had disk set  own-
         ership.  The metadevice state database is read in by the
         host performing the take,  and  the  shared  metadevices
         contained in the set are accessible.

         You can use this option to delete the last drive in  the
         disk  set,  because  this drive would implicitly contain
         the last state database replica.

         You can use -f option to delete hosts from a  set.  When
         specified  with  a partial list of hosts, it can be used
         for  one-host  administration.  One-host  administration
         could  be  useful  when  a  host  is  known  to  be non-
         functional, thus avoiding timeouts and failed  commands.
         When specified with a complete list of hosts, the set is
         completely deleted. It is  generally  specified  with  a
         complete  list  of  hosts  to  clean  up  after one-host
         administration has been performed.


     -h hostname...

         Specify one or more host names to be added to or deleted
         from  a disk set. Adding the first host creates the set.
         The last host cannot be deleted unless all of the drives
         within  the  set have been deleted. The host name is not
         accepted if all of the drives within the set  cannot  be
         found  on  the specified host. The host name is the same
         name found in /etc/nodename.


     -j

         Join a host to the owner list  for  a  multi-owner  disk
         set.  The concepts of take and release, used with tradi-
         tional disk sets, do  not  apply  to  multi-owner  sets,
         because multiple owners are allowed.

         As a host boots  and  is  brought  online,  it  must  go
         through  three  configuration levels to be able to use a
         multi-owner disk set:

             1.   It must be included in  the  cluster  nodelist,
                  which  happens  automatically  in  a cluster or
                  single-node sitatuion.

             2.   It must be added to the  multi-owner  disk  set
                  with  the -a -h options documented elsewhere in
                  this man page

             3.   It must join the set. When the  host  is  first
                  added to the set, it is automatically joined.
         On manual  restarts,  the  administrator  must  manually
         issue

           metaset -s multinodesetname -j


         to join the host to the owner list.  After  the  cluster
         reconfiguration, when the host reenters the cluster, the
         node is automatically joined to the set. The metaset  -j
         command  joins the host to all multi-owner sets that the
         host has been added to.  In  a  single  node  situation,
         joining  the  node  to the disk set starts any necessary
         resynchronizations.


     -L

         When adding a disk to a disk set, force the disk  to  be
         repartitioned  using the standard Solaris Volume Manager
         algorithm. See DESCRIPTION.


     -l length

         Set the size (in blocks) for the metadevice state  data-
         base  replica.  The length can only be set when adding a
         new drive; it cannot be changed on  an  existing  drive.
         The  default  (and  maximum)  size is 8192 blocks, which
         should be appropriate for most  configurations.  Replica
         sizes of less than 128 blocks are not recommended.


     -M

         Specify that the disk set to be created or modified is a
         multi-owner  disk  set that supports multiple concurrent
         owners.

         This option is required when creating a multi-owner disk
         set.  Its  use  is optional on all other operations on a
         multi-owner disk set and has no  effect.  Existing  disk
         sets cannot be converted to multi-owner sets.


     -o

         Return an exit status of 0 if the local host or the host
         specified  with  the  -h option is the owner of the disk
         set.


     -P

         Purge the named disk set from  the  node  on  which  the
         metaset  command  is run. The disk set must not be owned
         by the node that runs this command. If the node does own
         the disk set, the command fails.

         If you need to delete a disk set but cannot take  owner-
         ship of the set, use the -P option.

         This option is not for use with a multi-owner disk set.


     -q

         Displays  an  enumerated  list  of  tags  pertaining  to
         ``tagged data'' that can be encountered during a take of
         the ownership of a disk set.

         This option is not for use with a multi-owner disk set.


     -r

         Release ownership of a disk set. All of the disks within
         the  set are released. The metadevices set up within the
         set are no longer accessible.

         This option is not for use with a multi-owner disk set.


     -s setname

         Specify the name of a disk set on which  metaset  works.
         If no setname is specified, all disk sets are returned.


     -t

         Take ownership of a disk set safely.  If  metaset  finds
         that  another  host  owns  the  set, this host is not be
         allowed to take ownership of the set. If the set is  not
         owned  by  any  other host, all the disks within the set
         are owned by the host on which metaset was executed. The
         metadevice  state  database  is  read in, and the shared
         metadevices contained in the set become accessible.  The
         -t  option  takes  a  disk set that has stale databases.
         When the databases are stale, metaset  exits  with  code
         66, and prints a message. At that point, the only opera-
         tions permitted are the addition and deletion of  repli-
         cas.  Once  the addition or deletion of the replicas has
         been completed, the disk  set  should  be  released  and
         retaken to gain full access to the data.

         This option is not for use with a multi-owner disk set.


     -u tagnumber

         Once a tag has been selected, a subsequent take with  -u
         tagnumber  can be executed to select the data associated
         with the given tagnumber.


     w

         Withdraws a host from the owner list for  a  multi-owner
         disk  set.  The  concepts of take and release, used with
         traditional disk sets, do not apply to multi-owner sets,
         because multiple owners are allowed.

         Instead of releasing a set, a host can issue

           metaset -s multinodesetname -w


         to withdraw from the owner list.  A  host  automatically
         withdraws  on a reboot, but can be manually withdrawn if
         it should not be able to use the set, but should be able
         to rejoin at a later time. A host that withdrew due to a
         reboot can still appear joined from other hosts  in  the
         set until a reconfiguration cycle occurs.

         metaset -w withdraws from ownership of  all  multi-owner
         sets of which the host is a member. This option fails if
         you attempt to withdraw  the  master  node  while  other
         nodes  are  in the disk set owner list. This option can-
         cels all resyncs running on the node. A cluster reconfi-
         guration  process that is removing a node from the clus-
         ter membership list effectively withdraws the host  from
         the ownership list.


     -y

         Execute  a  subsequent  take.  If  the  take   operation
         encounters  ``tagged  data,''  the  take operation exits
         with code 2. You can then run the metaset  command  with
         the -q option to see an enumerated list of tags.


EXAMPLES
     Example 1 Defining a Disk Set


     This example defines a disk set.


       # metaset -s relo-red -a -h red blue




     The name of the disk set is relo-red. The names of the first
     and  second hosts added to the set are red and blue, respec-
     tively. (The hostname is found in /etc/nodename.) Adding the
     first  host  creates the disk set. A disk set can be created
     with just one host, with the second added  later.  The  last
     host  cannot  be  deleted until all of the drives within the
     set have been deleted.


     Example 2 Adding Drives to a Disk Set


     This example adds drives to a disk set.


       # metaset -s relo-red -a c2t0d0 c2t1d0 c2t2d0 c2t3d0 c2t4d0 c2t5d0



     The name of the previously created disk set is relo-red. The
     names  of  the  drives  are  c2t0d0, c2t1d0, c2t2d0, c2t3d0,
     c2t4d0, and c2t5d0. There is no slice identifier  ("sx")  at
     the end of the drive names.


     Example 3 Adding Multiple Mediator Hosts


     The following command  adds  three  mediator  hosts  to  the
     specified disk set.


       # metaset -s mydiskset -a -m myhost1,alias1 myhost2,alias2 myhost3,alias3



     Example 4 Purging a Disk Set from the Node


     The following command purges the disk set relo-red from  the
     node:


       # metaset -s relo-red -P



     Example 5 Querying a Disk Set for Tagged Data


     The following command queries the disk set  relo-red  for  a
     list of the tagged data:


       # metaset -s relo-red -q




     This command produces the following results:

       The following tag(s) were found:
        1 - vha-1000c - Fri Sep 20 17:20:08 2002
        2 - vha-1000c - Mon Sep 23 11:01:27 2002



     Example 6 Selecting a tag and taking a Disk set



     The following command selects a tag and takes the  disk  set
     relo-red:


       # metaset -s relo-red -t -u 2



     Example 7 Defining a Multi-Owner Disk Set


     The following command defines a multi-owner disk set:


       # metaset -s blue -M -a -h hahost1 hahost2




     The name of the disk set is blue. The names of the first and
     second  hosts  added  to  the  set  are hahost1 and hahost2,
     respectively. The hostname is found in /etc/nodename. Adding
     the  first host creates the multi-owner disk set. A disk set
     can be created with just one  host,  with  additional  hosts
     added  later.  The  last host cannot be deleted until all of
     the drives within the set have been deleted.


FILES
     /etc/lvm/md.tab             Contains list of metadevice con-
                                 figurations.


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),  metadetach(1M),
     metahs(1M),  metainit(1M),  metaoffline(1M), metaonline(1M),
     metaparam(1M),       metarecover(1M),        metarename(1M),
     metareplace(1M),  metaroot(1M), metassist(1M), metastat(1M),
     metasync(1M),    metattach(1M),     md.tab(4),     md.cf(4),
     mddb.cf(4), md.tab(4), attributes(5), md(7D)


NOTES
     Disk set administration, including the addition and deletion
     of  hosts  and  drives,  requires all hosts in the set to be
     accessible from the network.










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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