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nvfragpg(8)							  nvfragpg(8)



NAME

  nvfragpg - Display the pages of an AdvFS frag	file

SYNOPSIS

  /sbin/advfs/nvfragpg [-v] [-f] frag_id

  /sbin/advfs/nvfragpg [-v] [-f] frag_id page

  /sbin/advfs/nvfragpg volume_id  -b block

  /sbin/advfs/nvfragpg [-v] [-f] domain_id fileset_id -d dump_file

OPTIONS

  -b block
      Specifies	the logical block number of a disk block on an AdvFS volume.

  -d dump_file
      Specifies	the name of a file that	contains the output of this utility.

  -f  Display the frag file free list.

  -v  Display all the data in a	frag file.

OPERANDS

  frag_id
      Specifies	a frag file using the following	format:

      domain_id	fileset_id | [-F] dump_file
	  The dump_file	is a previously-saved copy of a	frag file. Use the -F
	  option to force the utility to interpret the dump_file as a file
	  name when it has the same name as a domain name.

  domain_id
      Specifies	an AdvFS file domain using the following format:

      [-r] [-D]	domain
	  By default, the utility opens	all volumes using block	device spe-
	  cial files. Specify the -r option to operate on the raw device
	  (character device special file) of the domain	instead	of the block
	  device. Specify the [-D] option to force the utility to interpret
	  the name you supply in the domain argument as	a domain name.

  volume_id
      Specifies	an AdvFS volume	using the following format:

      [-V] volume | domain_id volume_index
	  Specify the -V option	to force the utility to	interpret the name
	  you supply in	the volume argument as a volume	name. The volume name
	  argument also	can be a full or partial path name, for	example
	  /dev/disk/dsk12a or dsk12a. Specifying a partial path	name always
	  opens	the character device special file.

	  Alternatively, specify the volume by using arguments for its
	  domain, domain_id, and its volume index number, volume_index.

  fileset_id
      Specifies	an AdvFS fileset using the following format:

      [-S] fileset | -T	fileset_tag
	  Specify the [-S] option to force the command to interpret the	name
	  you supply as	a fileset name.	 Specify the fileset by	entering
	  either the name of the fileset, fileset, or the fileset's tag
	  number, -T fileset_tag.

  page
      Specifies	the file page number of	a file.

DESCRIPTION

  Use the nvfragpg utility to display information about	frag file metadata.

  Each fileset in an AdvFS domain has one frag file.  Frag files are collec-
  tions	of file	fragments.  The	file fragments in a frag file are grouped
  together by file fragment size into 16-page groups.  File fragments of 1
  Kbyte	or less	are collected in one group; file fragments more	than 1 Kbyte
  up to	2 Kbytes are collected in another group; and so	on, up to a group
  that contains	file fragments that are	more than 7 Kbytes up to 8 Kbytes.

  The first 1024 bytes of each group in	a frag file contains the metadata for
  the file fragments in	the group.

  A group is 128 Kbytes, so a group that collects 1 Kbyte fragments can	hold
  at most 127 fragments, a group that collects 2 Kbyte fragments can hold at
  most 63 fragments, and so on.	 A group that collects 7 Kbyte fragments can
  hold at most 18 fragments.

  Displaying a Summary


  The utility can display summary information about all	pages in a frag	file.
  For example, you can display a summary of all	the pages of the frag file
  for domain_1 fileset_1 by entering the following command:

       # /sbin/advfs/nvfragpg domain_1 fileset_1

  The -f option	displays which groups are on the free list for each frag
  type.	 The -v	option displays	the frag type of each group. The following
  command displays the type of each group and the free list for	each frag
  type:

       # /sbin/advfs/nvfragpg -v -f domain_1 fileset_1

  Displaying One Frag File Page


  You can specify that the utility display the metadata	from a single group
  of the frag file by specifying a page	in the group.  For example, you	can
  display the metadata from one	group of the frag file for fileset_1 in
  domain_1 by entering the following command:

       # /sbin/advfs/nvfragpg domain_1 fileset_1 16

  Because the metadata for the group is	only on	the first page of any group,
  the page option is rounded down to the next lower multiple of	16.


  Displaying Corrupted Volumes


  If an	AdvFS volume has become	corrupted, the metadata	needed to find the
  frag file can	be missing.  However, you can specify a	logical	block number
  (for a disk block) to	display	it, forcing the	utility	to interpret the
  block	as frag	file metadata.

  For  example,	to display the metadata	on the frag page that contains logi-
  cal block number 1024	on volume 2 of AdvFS domain_1, use the following com-
  mand:

       # /sbin/advfs/nvfragpg domain_1 2 -b 1024

  If the specified block is not	on a page boundary it is rounded down.

  Saving a Frag	File


  Use the utility to read the frag file	and save its metadata to another
  file.

  For example, to save the frag	file metadata from a domain and	volume index
  domain 2 on a	file named dump_domain.2, enter	the following command:

       # /sbin/advfs/nvfragpg domain 2 -d dump_domain.2

  Later, you can examine the file dump_domain.2	to obtain a summary of its
  frag file metadata by	entering the following command:

       # /sbin/advfs/nvfragpg dump_domain.2

NOTES

  An active domain, which is a domain with one or more of its filesets
  mounted, has all of its volumes opened using block device special files.
  These	devices	cannot be opened a second time without first being unmounted.
  However, the character device	special	files for the volumes can be opened
  more than once while still mounted.

  It can be misleading to use this utility on a	domain with mounted filesets
  because the utility does not synchronize its read requests with AdvFS	file
  domain read and write	requests.

  For example, the AdvFS can be	writing	to the disk as the utility is reading
  from the disk.  Therefore, when you run the utility, metadata	may not	have
  been flushed in time for the utility to read it and consecutive reads	of
  the same file	page may return	unpredictable or contradictory results.	[The
  domain is not	harmed.]

  To avoid this	problem, unmount all the fileset in the	domain before using
  this utility.

RESTRICTIONS

  The utility can fail to open a block device, even when there are no
  filesets mounted for the domain and the AdvFS	daemon,	advfsd is running.
  The daemon, as it runs, activates the	domain for a brief time.  If the
  utility fails	in this	situation, run it again.







EXIT STATUS

  The utility returns a	0 (zero) on success, otherwise it returns a nonzero
  value	and an error diagnostic.


FILES

  /sbin/advfs/nvfragpg
      Specifies	the command path.

  /etc/fdmns/domain_name
      Specifies	the AdvFS volumes in domain_name.

SEE ALSO

  Commands: nvbmtpg(8),	nvlogpg(8), nvtagpg(8),	vfilepg(8), vsbmpg(8)