nvbmtpg - Display pages of an AdvFS BMT file
/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
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
Table (RBMT) is to be displayed, instead of information
about the BMT. Specifies the logical block number of
a disk block on an AdvFS volume. 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.
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: Specify 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 special
file.
Alternatively, specify the volume by using arguments
for its domain, domain_id, and its volume
index number, volume_index. Specifies 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 fileset_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.
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 [Toc] [Back]
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 [Toc] [Back]
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 [Toc] [Back]
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 entering 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 primary 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 [Toc] [Back]
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 [Toc] [Back]
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 [Toc] [Back]
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 [Toc] [Back]
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 [Toc] [Back]
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. Therefore, 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 [Toc] [Back]
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 [Toc] [Back]
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 without 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
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.
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.
The utility returns a 0 (zero) on success, otherwise it
returns a nonzero value and an error diagnostic.
Specifies the command path. Specifies the AdvFS volumes
in domain_name
Commands: vfilepg(8), nvfragpg(8), nvlogpg(8), vsbmpg(8),
nvtagpg(8), tag2name(8)
nvbmtpg(8)
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