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



 NAME
      vxdisk - define and manage VERITAS Volume Manager disks

 SYNOPSIS
      vxdisk [-g diskgroup] addregion region_type disk offset length

      vxdisk [-g diskgroup] check disk ...

      vxdisk clearimport accessname ...

      vxdisk [-Bf] define accessname [attribute ...]

      vxdisk getctlr accessname

      vxdisk [-Bf] init accessname [attribute ...]

      vxdisk [-g diskgroup] [-o alldgs] [-qs] list [disk ...]

      vxdisk offline accessname ...

      vxdisk -a online

      vxdisk online accessname ...

      vxdisk rm accessname ...

      vxdisk [-g diskgroup] rmregion region_type disk offset [length]

      vxdisk [-g diskgroup] set disk [attribute ...]

      vxdisk scandisks

 DESCRIPTION
      The vxdisk utility performs basic administrative operations on disks.
      Operations include initializing and replacing disks, as well as taking
      care of some book-keeping necessary for the disk model presented by
      VERITAS Volume Manager (VxVM).

      accessname refers to the disk access name, while disk represents the
      disk media name.	vxdisk accesses disks based on disk access names,
      which are system-specific names that relate to disk addresses.  Disk
      access names are in the form c#t#d#, which define a controller number
      (c#), a SCSI target ID (t#), and a SCSI logical unit number (d#).
      Disk access names relate directly to device node names in the /dev/dsk
      and /dev/rdsk directories.

      VxVM 3.2 introduced enclosure-based naming as an alternative way of
      referring to disk access names. If enabled, this scheme maps disk
      access names relative to their enclosure. For example, disks in the
      enclosure ENC0 would be assigned access names ENC0_0, ENC0_1 and so
      on.



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



      Operations that take an accessname argument (see the SYNOPSIS section)
      accept only disk access names, as defined in the previous paragraph.
      Operations that take a disk argument can take disk access names or
      disk media names (for example, disk01).  For such operations, a disk
      group can be specified with -g to disambiguate disk media names that
      are used in more than one disk group.

      Physical disks in VxVM are assumed to be movable, and are usually
      identified by a unique disk ID stored on the physical disk, rather
      than by a disk device node.  This allows disks to be moved to
      different SCSI target IDs or to different controllers without
      affecting correct operation.

      VxVM maintains known disk device address information in a set of disk
      access records, which are stored in the rootdg disk group
      configuration.  These records are named based on the disk access name.
      These disk access records are normally used solely to identify which
      physical disks exist, based on disk IDs stored on the disks
      themselves.  Operations for vxdisk other than init and define require
      specification of defined disk access records.

      Physical disks contain public regions, which are used for allocating
      subdisks.	 They can also contain private regions, which are used for
      storing private VERITAS Volume Manager information.  Private regions
      are structured regions, and are maintained entirely by VxVM.  Private
      regions contain the following structures:

      Disk Header
		Each private region contains exactly two copies of a disk
		header, which defines the unique disk ID, disk geometry
		information, and disk group association information.  Two
		copies are created so that one copy can be lost (due to I/O
		failures) without causing use of the disk to be lost.  The
		primary copy of the disk header is stored in block zero of
		the private region.  The alternate copy is stored within the
		first 256 sectors.  If the primary copy is unreadable or
		unusable, VxVM searches the first 256 sectors of the private
		region for the alternate copy.

      Table of Contents
		A linked list of blocks, pointed to by the disk header, that
		define additional structures in the private and public
		regions.  The table of contents blocks define disk group
		configuration copy locations, log copy locations, and
		reserved regions carved from the public region.	 Each link
		block in the table of contents is replicated at the
		beginning and end of the private region.  If the primary
		copy of any one link block is unreadable or unusable, the
		alternate copy of that link is used.





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



      Configuration Copies
		A disk normally contains one disk group configuration copy,
		according to the number specified when the disk was
		initialized using the vxdisk init operation (explained
		later).	 When a disk is added to a disk group, the disk
		group's persistent configuration records are written to each
		copy.  For disks that are not associated with a disk group,
		the space allocated for configuration copies is unused.
		Each disk group requires at least one usable configuration
		copy.  Preferably there should be at least four copies,
		allocated between at least two disks.  This allows one disk
		to be lost totally, while still preserving sufficient
		redundancy for recovering from simple read failures.

      Disk Group Log Copies
		A disk normally contains one disk group log copy.  The
		number of log copies is set to the same as the number of
		configuration copies for the disk (as explained in the
		Configuration copies section above).  These logs are written
		by the kernel when certain types of actions are performed:
		transaction commits, plex detaches resulting from I/O
		failures, total dirty region log (DRL) failures, the first
		write to a volume, and volume close.  After a crash or a
		clean reboot, this log information is used to recover the
		state of a disk group just prior to the crash or reboot.
		Each disk group requires at least one usable disk group log
		copy.  As with configuration copies, it is preferable to
		have at least four log copies, allocated between at least
		two disks.

      For a single disk, the disk header and the table of contents blocks
      are critical data structures.  At least one copy of the disk header,
      and at least one copy of each table of contents block, must be
      readable and usable, or else the disk itself is unusable and must be
      reinitialized.

      Within disk groups, disk group configuration and log copies are
      critical data structures.	 At least one complete configuration copy
      and log copy must be readable and usable, or the disk group is
      unusable and must be reinitialized.

      All disk group association information is stored in the disk header
      within private regions.  This information consists of a disk group
      name, disk group unique ID, and a host ID.  When the system boots,
      VxVM scans for disks that are stamped with the system's host ID.	Each
      represented disk group is imported automatically.	 Disks with a non-
      matching host ID are not imported automatically, and cannot be used
      until the host ID is cleared with the clearimport operation.

      The behavior of the vxdisk utility depends upon the keyword specified
      as the first operand.



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



 KEYWORDS
      addregion Adds a new entry to the table of contents in a disk's
		private region.	 The new entry defines a region of disk that
		is relative to the public region, and that is reserved for a
		particular use.	 The offset and length operations indicate
		the location and extent of the region.	Currently, the only
		region type that can be defined is:

		reserve	  Masks out a region of disk that should be reserved
			  for purposes other than use by VxVM.	This could
			  be used, for example, to mask out a boot file
			  system that cannot be used for subdisk allocation,
			  or to mask out a region containing blocks that are
			  used for bad-block or bad-track replacement.

		Adding a region fails if a subdisk or region is already
		allocated over the requested region.

		The addregion functionality is currently unimplemented for
		any of the existing disk types.

      check	Determines the usability of the specified disks.  A disk is
		considered usable if VxVM can write and read back at least
		one of the disk headers that are stored on the disk.  If a
		disk in a disk group is unusable, VxVM detaches it from its
		disk group, and all subdisks stored on the disk become
		invalid.  The subdisks remain invalid until the unusable
		disk is replaced or the disk media record is reassigned to a
		different physical disk.

		For shared disks, VxVM detaches an unusable disk only if the
		disk group's detach policy is set to global.  If the disk
		group detach policy is local, the disk is not detached.
		However, if hosts in the cluster do not indicate that a disk
		is usable, the disk is detached from the entire cluster.
		See vxedit(1M) for more information on setting disk group
		detach policies.

      clearimport
		Clears the host-specific import information stored on the
		indicated disks, and in the configurations stored on those
		disks.	This command may be necessary in cases where import
		information stored for a disk group becomes unusable, due to
		host failures, or due to a disk group being moved from one
		machine to another.

		This operation cannot be applied to disks that are in
		imported disk groups.

      define	Defines a disk access record, but do not initialize it.	 In
		order for VxVM to scan a disk, a disk access record must be



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



		defined for it.	 Thus, if you want to see what is on a new
		disk or you want to move a disk with a valid disk group from
		one system to another, you must first make it accessible by
		using vxdisk define.  You can use vxdisk list to see what is
		on the disk, or vxdg import to import a disk group that is
		on the disk.

		Attributes can be specified to define the access
		characteristics of the disk device.  Some attributes that
		can be set are:

		type=disk_type
			  The disk device access type.	See the init
			  operation definition for more details.

			  The various disk types support additional
			  attributes for the define operation.	See the
			  definition for each disk type, in the Disk Types
			  section.

		offline	  If specified, the disk is created in the offline
			  state.

		Normally, a define operation fails if the specified disk
		device is invalid, such as because no such disk currently
		exists.	 The -f option can be used to force definition of an
		unusable disk.	This can be useful if, for example, the disk
		device could be used after a reboot.  For example, if you
		intend to add a new controller and intend to move some
		existing disks to the new controller, you may need to define
		the new disk device addresses, even though they are not
		usable until you shutdown and reconfigure your disks.

		If specified, the -B option initializes the VERITAS Volume
		Manager private region to begin at block number 2144.  This
		block is designated as the private region offset for a
		VERITAS Volume Manager root disk.  Without this option, the
		private region is initialized to start at the default block
		number 128.

      getctlr	Returns the name of the controller associated with a given
		disk access name.

      init	Initializes regions of a disk used by VxVM.  This involves
		installing a disk header and writing an empty configuration
		on the disk.  The accessname operand identifies the disk.
		Normally, this command fails if the disk already contains an
		apparently valid disk header.  The -f option can be used to
		override this and to force initialization of the disk.	A
		disk that is a member of an imported disk group cannot be
		initialized.



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



		The vxdisk init operation creates a disk access record for a
		disk (if one does not already exist), and sets its state to
		online.	 Disks can be initialized when the root
		configuration is disabled, in which case the disk header is
		initialized, but the disk is not added to the permanent list
		of known disks until the root configuration is enabled.

		Any attribute operands override default values assigned for
		various disk attributes.  Some attributes that can be set
		are:

		type=disk_type
			  The disk device access type, which is a system-
			  specific name identifying a class of strategies
			  for accessing disks and for managing private and
			  public regions.  For example, disk types could
			  indicate network disks or a volatile RAM disk that
			  may not require the storage of any private data.

			  The various disk types support additional
			  attributes for the init operation.  See the
			  definition for each disk in the Disk Types
			  section.

		offline	  Leaves the device in the offline state initially.
			  This is used only if this operation is defining a
			  new disk access record.

		If specified, the -B option initializes the VERITAS Volume
		Manager private region to begin at block number 2144.  This
		block is designated as the private region offset for a
		VERITAS Volume Manager root disk.  Without this option, the
		private region is initialized to start at the default block
		number 128.

      list	Lists path type and states along with the detailed
		information on the specified disks.  The state is listed as
		enabled or disabled. If no disk arguments are specified,
		then print an one-line summary for all disk access records
		known to the system.  If disk arguments are specified, then
		print a full description of the contents of the disk header
		and of the table of contents for each named disk.  If no
		disk arguments are specified, but a disk group is specified
		with -g, then list only those disks added to the specified
		disk group.

		If the -s option is specified, then list important
		information from the disk header.  With -s, the output
		format is the same whether or not accessname arguments are
		specified.  The information printed with -s includes the
		disk ID, the host ID (if the disk is or was imported), and



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



		the disk group ID and disk group name (if the disk is a
		member of a disk group).

		If the -q option is specified, then no header is printed
		describing output fields.  This option has no effect with
		the long formats generated with -s or with accessname
		arguments.

		When -o alldgs is specified without -s and -g, a one line
		summary shows all disk to disk group associations.  The disk
		group column shows imported disk groups as normal and shows
		all other disk groups in parentheses.

      offline	Declares the disk devices named by the accessname arguments
		to be in the offline state.  This disables checking of the
		disk in searching for particular disk IDs, or for the set of
		disks in a particular disk group.  This operation cannot be
		applied to disks that are members of an imported disk group.

		Take a disk offline if the disk is not currently accessible,
		and if accessing the disk has a negative impact on the
		system.	 For example, disk drivers on a some operating
		systems can cause system panics or hangs if an attempt is
		made to access disks that are not accessible.  In other
		operating systems, attempts to access inaccessible drives
		may take several seconds or minutes before returning a
		failure.

      online	Clears the offline state for a disk device.  This re-enables
		checking of the disk when searching for disk IDs, or for
		members of a disk group.  This can be used for disks that
		are already in the online state, provided that they are not
		in imported disk groups.  All internal information for an
		already online state disk is regenerated from the disk's
		private region.

		If -a is specified, re-online all online disks that are not
		currently in an imported disk group.  This can be used to
		force VxVM to re-scan all disk headers.

      rm	Removes the specified disk access records, by disk access
		name.

      rmregion	Frees a region of space that is allocated in the private or
		public region for a particular use.  Space that is freed
		from the public region becomes usable for subdisk creation.
		The arguments to rmregion must match the arguments used when
		adding the region with vxdisk addregion except for the
		optional length argument which can be excluded for the
		remove.




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



		The rmregion functionality is currently unimplemented for
		any of the existing disk types.

      scandisks Initiates a rescanning of devices in OS device tree by VxVM
		and triggers a DMP reconfiguration. In this manner disks can
		be dynamically configured and multipathed by VxVM.

      set	Changes some set of attributes for a disk.  The attributes
		are either simple names (used to turn on an on/off
		attribute), or can be of the form attrname=value, to
		indicate a value for a particular attribute.

 Hardware-Specific Note
      Some environments provide guidelines to optimize VxVM's interaction
      with intelligent storage systems. If these guidelines are present,
      VxVM follows them when initializing disks, creating volumes or
      allocating space for volumes. These rules cannot be overridden.

 Disk Types
      Two basic disk types are provided with VxVM.  Additional types may be
      added for use with particular operating systems.	The default is a
      simple type.

 Nopriv Disks
      The simplest disk type is nopriv, which defines a disk that has no
      private region, and that consists only of space for allocating
      subdisks.	 Configuration and log copies cannot be stored on such
      disks, and such disks do not support reserved regions defined with
      vxdisk addregion.	 Because nopriv disks are not self identifying, VxVM
      cannot track the movement of such disks on a SCSI chain or between
      controllers.

      nopriv devices are most useful for defining special devices (such as
      volatile RAM disks) that you wish to use with VxVM, but that cannot
      store private regions.  A RAM disk cannot store a meaningful private
      region, because data written to a RAM disk may not survive a reboot.

      Initializing a nopriv device with vxdisk init creates a disk access
      record in the rootdg configuration, but does not write to the disk.
      The disk ID for nopriv devices is stored in the disk access record in
      the rootdg configuration.

      Attributes that can be used with the vxdisk init and define operations
      for the nopriv device type are:

      publen=length or len=length
		The usable length of the device.  This is required if there
		is no system-defined procedure for determining the disk
		length; otherwise, a suitable default is computed.





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



      puboffset=offset or offset=offset
		The offset within the device for the start of the usable
		region.	 This defaults to 1. This can be used if it is
		necessary to skip over some region reserved by the operating
		system.	 If an offset is specified, then the default disk
		length is adjusted accordingly.

      volatile	If this attribute is specified, the disk is considered to
		have volatile contents (that is, the disk contents are not
		expected to remain consistent across a system reboot).
		Subdisks and plexes defined on disks with the volatile
		attribute inherit that attribute.  The vxvol start operation
		interprets volatile plexes as requiring a complete revive
		from other plexes in the same volume.

      The vxdisk define operation, with the nopriv device type, takes the
      same attributes as the init operation.  In addition, define takes the
      following attribute:

      diskid=newdiskid
		This attribute sets the disk ID to the newdiskid value in
		the disk access record for the nopriv disk.

 Simple Disks
      The simple type presumes that the public and private regions are
      stored on the same disk, with the public region following the private
      region.

      Attributes that can be defined with vxdisk define for simple are:

      configlen=length
		The size to reserve for each copy of the configuration
		stored on the disk.  The default size is based on the size
		of the private area and the number of configuration copies
		requested, and leaves some space free for uses other than
		the configuration copies.

      loglen=length
		The size to reserve in the private region for each log
		region.	 This size limits the number of kernel-initiated
		detach operations that can be logged against the disk group.
		The default is about 15% of the size of the configuration
		copies.	 It is advised that the log sizes be kept as 15% of
		the configuration copy size.

      nconfig=count
		The number of configuration copies to store on the disk.
		This defaults to 1.  This can be set to 0 to indicate that
		no configurations are to be stored on the disk.	 VxVM
		automatically enables and disables the configuration copy.
		It maintains a level of redundancy in configuration copies



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



		that allows the configuration to be recovered from the loss
		of multiple disks.  See the vxdg nconfig parameter for more
		information.

      nlogs=count
		The number of log regions to allocate on the disk.  Logs
		regions are used for storing any plex detaches that happen
		within the disk group.	This number defaults to 1.  VxVM
		automatically enables and disables the configuration copy.
		It maintains a level of redundancy in configuration copies
		that allows the configuration to be recovered from the loss
		of multiple disks.  Refer to the vxdg(1M) nlog parameter for
		more information.

      publen=length or len=length
		The length of the public region.  If not specified, the
		length of the public region is computed from available
		system-specific disk size information.	If no such
		information is available, a public region length must be
		specified in this command.  The default public region length
		is adjusted to account for the private region, or for any
		specified public or private region offsets.

      privlen=length
		The length of the private region. If this is not specified,
		then a default is chosen. For the simple type, the default
		size is 2048 blocks.  The maximum possible size of the
		private region is 524288 blocks.

 Auto-Configured Disks
      On some systems, VxVM can ask the operating system for a list of known
      disk device addresses.  On such systems, some device addresses are
      auto-configured into the rootdg disk group when vxconfigd is started.
      Auto-configured disks are always of type simple, with default
      attributes.

      Auto-configured devices can be removed, if necessary, using vxdisk rm.
      When removed, explicitly defined devices can be defined to override
      any auto-configured devices.  When the system reboots, no auto-
      configured disk devices are added to the rootdg disk group that would
      share a disk with an explicitly configured disk device.

      Auto-configured devices can be disabled and re-enabled using the
      offline and online operations.  However, the offline state is not
      stored persistently.  If you need to persistently offline a device at
      a particular address, convert the address to use an explicit device
      record.  To do this, remove the auto-configured device, and use vxdisk
      define to create an explicitly configured device.

 EXAMPLES
      This example sets the powerfail timeout on disk01.



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



	   vxdisk set disk01 pfto=seconds


      The set functionality is currently unimplemented for any of the
      existing disk types.

      Use the getctlr keyword to return the controller associated with a
      disk that is specified by its enclosure-based disk access name.

	   vxdisk getctlr JBOD0_5


 SEE ALSO
      pfto(7), vxconfigd(1M), vxdg(1M), vxedit(1M), vxintro(1M), vxvol(1M)








































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