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 vxrelayout(1M)			  VxVM 3.5		      vxrelayout(1M)
				 1 Jun 2002



 NAME
      vxrelayout - convert online storage from one layout to another

 SYNOPSIS
      vxrelayout [-f] [-g diskgroup] [-o useopt]
      [-R request_portal] [-t tasktag] [-T taskid] [-U usetype] reverse
      volume

      vxrelayout [-f] [-g diskgroup] [-o useopt]
      [-R request_portal] [-t tasktag] [-T taskid] [-U usetype] start volume

      vxrelayout status volume

      vxrelayout help | -H

 DESCRIPTION
      Online relayout is a process where storage in a volume or a plex is
      converted from one layout to another maintaining data availability at
      all times.  You can convert any supported VERITAS Volume Manager
      (VxVM) layout to another and change the stripe width or the number
      columns. You can also perform only stripe width and column changes.

      The transformation of a volume or a plex must be initiated using the
      vxassist(1M) utility.  vxassist creates necessary infrastructure and
      storage needed to perform the layout transformation and invokes
      vxrelayout internally to actually perform the transformation.

	   Note: The relayout operation internally generates unique data
	   object names (for example, v2-Dp02) when it converts a volume to
	   a specified destination layout.

	   Because vxrelayout depends on vxassist to do all the setup before
	   a layout transformation can begin, the vxassist utility must be
	   used to initiate any layout transformation.	The vxtask(1M)
	   utility can monitor the state of an ongoing transformation.

      Because these transformations are time consuming (mainly depending on
      the volume size and chunk size), they can be interrupted because of a
      system crash, I/O failure, or the user voluntarily stopping the
      transformation process either by aborting the task associated with the
      transformation using vxtask or by killing the transformation process.
      It is not advisable to use kill -9 to stop the transformations.  The
      vxrelayout utility can be used to continue or reverse a transformation
      process because of such interruptions.

      VERITAS Volume Manager responses to possible interruptions are:

      I/O Failure	  vxrelayout utility exits with an error on stderr.
			  The vxrelocd(1M) daemon tries to relocate the
			  failed subdisks. If it succeeds, it invokes
			  vxrecover(1M), which in turn invokes vxrelayout to



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 vxrelayout(1M)			  VxVM 3.5		      vxrelayout(1M)
				 1 Jun 2002



			  continue the transformation. An I/O failure is
			  transparent to the user if the relocation
			  succeeds. If relocation fails, the transformation
			  process is not restarted.

      System Crash	  On a reboot after a system crash, vxrecover starts
			  all startable volumes, invoking vxrelayout on
			  appropriate volumes and plexes.

			  If the user stops vxrelayout, then the
			  transformation process can be reversed or
			  continued by invoking vxrelayout manually.

      The first operand is a keyword that determines whether a layout
      conversion is to be continued, reversed, or to display the status of
      any existing transformation in the volume. For example, if a RAID-5
      volume is being converted to STRIPED volume, reversal of such an
      operation will revert all data and storage in STRIPED format to the
      RAID-5 format. A reversal of a reversal is equivalent to a continue.

      Even though such a capability of direction change can be used ad
      infinitum, it has been provided with an objective to react to
      unforeseen situations. It is advisable that such direction changes are
      done with care.

      The direction of a transformation can be determined using the status
      operation provided in the vxrelayout utility. This command will
      determine if any plex in the volume is being transformed and display
      its characteristics.

      The second operand is the name of the topmost volume to which the plex
      undergoing relayout is attached. If there are multiple plexes in the
      volume and only one of them is being transformed, the vxrelayout
      utility  will select the appropriate plex using the supplied volume
      name.  It should be noted that there can only be one relayout
      operation happening in a volume at any instant of time. A specific
      disk group can be forced with -g diskgroup.

      This operation can be applied only to disk groups with version 60 or
      above (see vxdg(1M)), and only to one disk group at a time.  The
      supported storage layouts are:

	   +  concatenated

	   +  striped

	   +  RAID-5

	   +  mirrored





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 vxrelayout(1M)			  VxVM 3.5		      vxrelayout(1M)
				 1 Jun 2002



	   +  striped-mirror

	   +  concatenated-mirror
      See the VERITAS Volume Manager Administrator's Guide for more
      information.

 KEYWORDS
      help	Displays information on vxrelayout usage.

      reverse	Reverses a discontinued layout conversion. This operation
		determines the current state and direction of a layout
		transformation and reverse where it was left off since it
		was last stopped. It is imperative that any existing layout
		transformation process is stopped before this operation is
		applied.

      start	Continues a discontinued layout conversion. This operation
		determines the current state and direction of a layout
		transformation and continue where it was left off since it
		was last stopped. It is imperative that any existing layout
		transformation process is stopped before this operation is
		applied.

      status	Displays the status of a discontinued or an ongoing layout
		conversion.  This operation displays the characteristics of
		the source and the destination layout, such as the layout,
		number of columns, and stripe width.  It also displays
		whether the transformation is ongoing or stopped, and the
		actual relayout percentage completed.

 OPTIONS
      -f	Forces a continue or reverse of a layout transformation.
		This is considered potentially dangerous or questionable to
		use as using this flag may result in loss of data. This
		permits a limited set of operations that would otherwise be
		disallowed:

		+    It is possible that an I/O failure during a layout
		     transformation caused some plexes to detach, If the
		     user still wants to continue or reverse such a
		     transformation, this flag will have to be used to tell
		     vxrelayout to ignore the fact some plexes have failed.
		     There is no guarantee that this operation will succeed.

		+    vxrelayout shrinks any existing file system on a volume
		     if the layout transformation causes the volume size to
		     decrease. If the user does not want vxrelayout to
		     shrink the file system but wants to still perform the
		     layout conversion, this flag must be used.





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 vxrelayout(1M)			  VxVM 3.5		      vxrelayout(1M)
				 1 Jun 2002



      -g diskgroup
		Specifies the disk group for the operation, either by disk
		group ID or by disk group name.	 By default, the disk group
		is chosen based on the name operands.

      -o useopt Passes in usage-type-specific options to the operation.	 A
		certain set of operations are expected to be implemented by
		all usage types:

		slow[=iodelay]
		     Reduces the system performance impact of copy
		     operations.  Copy operations are usually a set of short
		     copy operations on small regions of the volume
		     (normally from 16 kilobytes to 128 kilobytes).  This
		     option inserts a delay between the recovery of each
		     such region.  A specific delay can be specified with
		     iodelay as a number of milliseconds; otherwise, a
		     default is chosen (normally 250 milliseconds).

		iosize=size
		     Performs copy operations in regions with the length
		     specified by size, which is a standard VERITAS Volume
		     Manager length number (see vxintro(1M)).  Specifying a
		     larger number typically causes the operation to
		     complete sooner, but with greater impact on other
		     processes using the volume.  The default I/O size is
		     typically 32 kilobytes.

		     Note: These parameters can also be changed using the
		     vxtask utility during an online relayout.

		bg   Run the vxrelayout operation in the background.

      -R request_portal
		Specifies a rendezvous file path name for regular
		configuration and query requests.  /etc/vx/vold_request is
		the default.

      -t tasktag
		If any tasks are registered to track the progress of the
		operation, marks them with the tag tasktag.  The tag
		specified by tasktag is a sequence of up to 16 alphanumeric
		characters.

      -T taskid Associates new tasks with the specified parent task ID.

      -U usetype
		Limits the operation to apply to this usage type.  Attempts
		to affect volumes with a different usage type will fail.





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 vxrelayout(1M)			  VxVM 3.5		      vxrelayout(1M)
				 1 Jun 2002



      -H	Displays information on vxrelayout usage.

 EXIT CODES
      vxrelayout exits with a non-zero status if the operation fails.  A
      non-zero exit code is not a complete description of the problem; it
      only indicates the first condition that prevented further execution.

      See vxintro(1M) for a list of standard exit codes.

 EXAMPLES
      Check the progress of conversion of the volume homevol:

	   vxrelayout status homevol


      Restart conversion of the volume homevol at a slow rate in the
      background (layout conversion having previously been stopped by using
      the pause keyword in vxtask):

	   vxrelayout -o slow,bg start homevol


      Reverse conversion of the volume homevol (layout conversion having
      previously been stopped):

	   vxrelayout reverse homevol


 SEE ALSO
      kill(1), vxassist(1M), vxdg(1M), vxintro(1M), vxrecover(1M),
      vxrelocd(1M), vxtask(1M)

      VERITAS Volume Manager Administrator's Guide





















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