nvbmtpg(8)						      System Manager's Manual							nvbmtpg(8)

NAME

       nvbmtpg - Display pages of an AdvFS BMT file

SYNOPSIS

       /sbin/advfs/nvbmtpg [-R] [-v] { domain_id | bmt_id } [-f]

       /sbin/advfs/nvbmtpg [-R] [-v] bmt_id page [-f]

       /sbin/advfs/nvbmtpg [-R] [-v] bmt_id page mcell [-c]

       /sbin/advfs/nvbmtpg [-R] [-v] bmt_id [-a]

       /sbin/advfs/nvbmtpg [-R] [-v] domain_id fileset_id [file_id] [-c]

       /sbin/advfs/nvbmtpg [-R] [-v] { domain_id | volume_id } -l

       /sbin/advfs/nvbmtpg [-R] [-v] bmt_id  -s b block [-c]

       /sbin/advfs/nvbmtpg [-R] [-v] domain_id fileset_id -s f frag [-c]

       /sbin/advfs/nvbmtpg [-R] [-v] { bmt_id | domain_id  [fileset_id] } -s t tag [-c]

       /sbin/advfs/nvbmtpg [-R] [-v] volume_id	-b block [mcell]

       /sbin/advfs/nvbmtpg [-R] volume_id  -d dump_file

OPTIONS

       Display	all  the  pages  in  the BMT.  Specifies the logical block number of a disk block on an AdvFS volume.  Display the entire chain of
       mcells.	Alternatively, continue to search.  Specifies the name of a file that will hold the contents of the specified BMT  file.   Display
       the  number of free mcells.  Display the deferred delete list of mcells.  Specifies that information about the Reserved Bitmap Metadata Ta-
       ble (RBMT) is to be displayed, instead of information about the BMT.  Specifies the logical block number of a disk block on an  AdvFS  vol-
       ume.  When  you use this option, the utility searches the specified BMT file for a mcell that has an extent record for a file that contains
       the specified block.  Specifies the number of a file fragment in the frag file for a  fileset.  When  you  use  this  option,  the  utility
       searches  all  BMT  files (there is one on each AdvFS volume) for a mcell that: Belongs to a file in the specified fileset Has an attribute
       record that indicates the file is using the specified frag ID.  Specifies the file tag number.  When  you  use  this  option,  the  utility
       searches one or all of the BMT files for a mcell with this tag.	Display all the data in a specified mcell.

OPERANDS

       Specifies the BMT file on an AdvFS volume or a BMT file that has been saved by the utility as a dump_file.  Use the following format: Spec-
       ify the -F option to force the utility to interpret the name you supply as a file name.	Specifies an AdvFS file domain using the following
       format:	By  default,  the  utility  opens all volumes using block device special 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.  Specifies an AdvFS volume using the following format: 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 for the volume, for example /dev/disk/dsk12a or dsk12a. Specifying a partial path name always opens the character device spe-
       cial file.

	      Alternatively, specify the volume by using arguments for its domain, domain_id, and its volume index number,  volume_index.   Speci-
	      fies an AdvFS fileset using the following format: 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 file's fileset tag number,  -T  file-
	      set_tag.	Specifies a file name in the following format: Specify the file by entering either the fileset relative pathname, file, or
	      the file's tag number, -t file_tag.  Specifies the number of a metadata cell (mcell) in a BMT file.  Specifies the file page  number
	      of the BMT file.

DESCRIPTION

       The nvbmtpg utility formats, dumps, and displays pages of the Bitfile Metadata Table (BMT) files.

       For  Tru64  UNIX  Version 5.0 and beyond, the utility also formats, dumps, and displays pages of the Reserved Bitfile Metadata Table (RBMT)
       files.  RBMT files are metadata structures that extend BMT files.

       BMTs are composed of mcells.   Each file in an AdvFS domain is described by a collection of mcells.  The mcells for each file  are  chained
       together.  The first mcell in a chain is called the primary mcell.

       There is one BMT file on each volume of an AdvFS domain.

       A  BMT  file is an array of 8 Kbyte file pages, each page containing a header and an array of metadata cells (mcells). The purpose of a BMT
       file is to contain all the metadata for all files that are stored on an AdvFS volume.

       This utility has the following functions: Display a summary of the BMT on one AdvFS volume or a summary of all the BMT files (there is  one
       per  volume) in a domain.  Display a page of mcells or one mcell or a chain of mcells.  The page can be specified by a BMT page number or a
       volume block number. An mcell can be specified by a number or by specifying the primary mcell of a file.  Search for an mcell.  The  search
       can be for an extent that maps a volume block or a file that uses a given frag ID.

   Display a Summary of BMTs
       By  specifying  just  a	domain	and  (possibly) the -f option, you cause the utility to display a summary of the BMT on all volumes in the
       domain.	Without the -f option, the summary shows how long the BMT is, in pages. With the -f option, the summary  also  displays  how  many
       free mcells are in the BMT for each volume.

       For  example,  the  following  command causes the utility to read BMT page 0 (zero) in every volume of the domain and display the number of
       pages in each BMT, the number of extents used to describe the BMT, and the number of free mcells in BMT page 0:	#  /sbin/advfs/nvbmtpg	-r
       my_domain

       For  example, the following command causes the utility to read the entire BMT in every volume of the domain and display the number of pages
       in each BMT, the number of extents use, and the number of free mcells in BMT page 0.  In addition, the utility displays the number of  free
       mcells not on page 0: # /sbin/advfs/nvbmtpg my_domain -f

       Specifying  just  a  volume  (and  possibly  the  -f  option)  displays	a  summary  for  the  BMT  on  that  volume.   Two examples are: #
       /sbin/advfs/nvbmtpg -D my_domain 1 -f

       # /sbin/advfs/nvbmtpg dsk12c

   Displaying a BMT Page
       The utility can display information from a specified BMT page. It can display the whole page or one mcell on a page.   It can also  display
       all the mcells on an AdvFS volume.

       Each AdvFS volume contains its own BMT file, so you must specify the volume and the page to get the page you want to display.  For example,
       to display the first page  (page 0) of the BMT on volume /dev/disk/dsk5a, you would enter  the  following  command:  #  /sbin/advfs/nvbmtpg
       /dev/disk/dsk5a 0

       The volume can also be specified by domain name and volume index.  For example, to display page 0 or volume 1 of the domain_1 domain, enter
       the following command: # /sbin/advfs/nvbmtpg domain_1 1 0

       You can specify a single mcell to display.   For example, you could display mcell 5 on page 4 of the third AdvFS volume in the file  domain
       domain_1 by entering the following command: # /sbin/advfs/nvbmtpg domain_1 3 4 5

       To display all the mcells on dsk5a, enter the following command: # /sbin/advfs/nvbmtpg /dev/disk/dsk5a -a

									  Note

       This use of the command can generate megabytes of output: use it carefully.

   Displaying Primary mcells
       The  primary  mcell  of	a  file in an AdvFS domain is the first mcell in a chain of mcells that describe the file. The primary mcell for a
       fileset in an AdvFS domain is the first mcell in a chain of mcells that describes the fileset. Use this utility to locate and  display  the
       primary mcell of a file or a fileset.

       To  locate  the primary mcell (for either a file or a fileset) you must uniquely identify it in the command line. A fileset can be uniquely
       identified by its domain and fileset names. A file can be uniquely identified by its domain, fileset, fileset relative path name.

       For example, you can display the primary mcell for a file file_1 in a directory dir_1 in a fileset fileset_1 in a domain domain_i by enter-
       ing the following command: # /sbin/advfs/nvbmtpg domain_1 fileset_1 dir_1/file_1

       You can also display the primary mcell by its tag number. For example, if the file_1 had a tag number of 5, the command to display the pri-
       mary mcell for the file	would be: # /sbin/advfs/nvbmtpg domain_1 fileset_1 -t 5

									  Note

       If there is no danger of confusing tag 5 with a file named 5 in the root directory, then the -t option is optional.

   Displaying mcell Chains
       The mcells that describe one BMT file are chained, and are not necessarily contiguous. Use the [-c] option to display these  mcell  chains.
       For example, display the entire chain of mcells that describe the file named file_1 in the root directory of the fileset named fileset_1 in
       the domain named domain_1, enter the following command: # /sbin/advfs/nvbmtpg domain_1 fileset_1 file_1 -c

   Displaying the Deferred Delete List
       Each volume in a domain has a linked list of mcells which represent storage to be freed.  The -l option displays the mcells in  this  list.
       If  just  the  domain  is  specified,  the  option  displays  the  deferred  delete  list  for  every volume in the domain.  For example: #
       /sbin/advfs/nvbmtpg domain_1 -l

       If an AdvFS volume is specified, the option displays the deferred delete list for that volume.  For example: # /sbin/advfs/nvbmtpg dsk5c -l

   Displaying Corrupted Volumes
       If the volume is corrupted, the metadata structure needed to find specific mcells can be missing.  In this case, you  can  specify  a  disk
       block and the utility displays a page containing the specified disk block.

       For  example:   you  have  a corrupted AdvFS domain, but you have the logical block number of a BMT page.   To display logical block number
       1024 on AdvFS volume /dev/disk/dsk5c in AdvFS domain domain, forcing it to be formatted as a BMT page, you use  the  following  command:  #
       /sbin/advfs/nvbmtpg dsk5c -b 1024

       For  example:  you  have a corrupted AdvFS domain, but you have a domain and an index number and the logical block number of a BMT page. To
       display logical block number 1024 on AdvFS volume 2 in AdvFS domain domain, forcing it to be formatted as a BMT page, you use the following
       command: # /sbin/advfs/nvbmtpg domain 2 -b 1024

   Saving a BMT File
       Use  the  utility  to  read  the  BMT  file  and  save  it to another file. Later, you can use the utility to display information from this
       dump_file.

       For example, to save the BMT file from volume index 2 in a domain named domain_1 to a file  named  dump_domain.2  in  the  current  working
       directory, enter the following command: # /sbin/advfs/nvbmtpg domain_1 2 -d dump_domain.2

       Later,  you  can  examine  the  file  dump_domain.2  to	obtain	a  summary  of	its  BMT  pages,  by  entering	the  following	command: #
       /sbin/advfs/nvbmtpg dump_domain.2

       You can also use the utility to display other information from the dump_file, such as:  any mcell, a page of mcells, or the mcell free list
       in a page of mcells.

   Searching for Disk Blocks
       You  can  determine  which  file is using a logical block number by searching for and displaying the mcell that contains a file extent that
       includes that block. The mcell contains the fileset tag and the file tag number of the file that includes that  block.	Use  the  tag2name
       utility to find the file name.

       For  example,  you can search for a mcell record that describes the use of a disk block on an AdvFS volume.  If you want to determine which
       file was using logical block number 1234 on AdvFS volume dsk12c, you can enter the following command: #	/sbin/advfs/nvbmtpg  dsk12c  -s  b
       1234

       A  given block should only appear in one mcell.	However, a corrupted volume may have two or more extents describing the same block. There-
       fore, if you want to find the disk block shown above and continue the command, searching for any files that also have a	file  extent  that
       includes block 1234, you can enter the following command: # /sbin/advfs/nvbmtpg dsk12c -s b 1234 -c

   Searching for Fragment Files
       AdvFS  creates  one fragment file for each fileset in an AdvFS file domain.  You can determine the file that is using a given file fragment
       ID and display the primary mcell for that file.

       For example, if you want to determine which file in domain domain and fileset fileset was using the fragment id 1234,  you  can	enter  the
       following command: # /sbin/advfs/nvbmtpg domain fileset -s f 1234

       A  given  fragment  ID can only be used by one file in a fileset.  However, a corrupted fileset may have a given fragment ID used by two or
       more files.  Therefore, if you want to find the fragment file ID above and continue the command, searching for any  additional  files  that
       own the file fragment, you can enter the command: # /sbin/advfs/nvbmtpg domain fileset -s f 1234 -c

   Searching for a Specified Tag
       If  you	specify  a  domain,  a fileset and a file tag (as shown before in the section on displaying primary mcells) the utility uses other
       metadata files in the domain to find the primary mcell in the BMT. However, the utility can also search for a mcell with a given tag  with-
       out using any other metadata files if you specify the -s t option.

       This option searches a saved BMT file, or the BMT on one volume, or all the BMT files in a domain for an mcell with the tag you specify. If
       you specify a domain and fileset, the utility narrows the search to mcells that belong to the fileset.	However, if you specify a fileset,
       the  utility  must use other metadata files in the domain.  In this case, the search syntax displays the first mcell it finds that contains
       the specifed tag.  This mcell could be (but may not be) the primary mcell for the file.	To continue the search and display all mcells  for
       the specified tag, add the -c option.

       The following example searches all BMT files for mcells with tag 123: # /sbin/advfs/nvbmtpg domain_1 -s t 123 -c

       The following example searches a saved BMT file for mcells that belong to file tag 456: # /sbin/advfs/nvbmtpg save_bmt -s t 456 -c

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 con-
       tradictory 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  run-
       ning. 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

       Specifies the command path.  Specifies the AdvFS volumes in domain_name

SEE ALSO

       Commands: vfilepg(8), nvfragpg(8), nvlogpg(8), vsbmpg(8), nvtagpg(8), tag2name(8)

																	nvbmtpg(8)