nvfragpg - Displays the pages of an AdvFS frag file
/sbin/advfs/nvfragpg [-v] [-f] frag_id
/sbin/advfs/nvfragpg [-v] [-f] frag_id page
/sbin/advfs/nvfragpg volume_id -b block [-v] [-f]
/sbin/advfs/nvfragpg domain_id fileset_id -d dump_file
Specifies the logical block number of a disk block on an
AdvFS volume. Specifies the name of a file that contains
the output of this utility. Displays the frag file free
list. Displays all the data in a frag file.
Specifies a frag file using the following format: 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. 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 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. 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 fileset's tag number, -T fileset_tag.
Specifies the file page number of a file.
Use the nvfragpg utility to display information about frag
file metadata.
Each fileset in an AdvFS domain has one frag file. Frag
files are collections 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 Kb or less
are collected in one group; file fragments more than 1 Kb
up to 2 Kb are collected in another group; and so on, up
to a group that contains file fragments that are more than
6 Kb up to 7 Kb.
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 Kb, so a group that collects 1 Kb fragments
can hold at most 127 fragments, a group that collects 2 Kb
fragments can hold at most 63 fragments, and so on. A
group that collects 7 Kb fragments can hold, at most, 18
fragments.
Displaying a Summary [Toc] [Back]
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 gives more information
for 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 [Toc] [Back]
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 16-page group, the page option is rounded down
to the next lower multiple of 16.
Displaying Corrupted Volumes [Toc] [Back]
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 logical block number 1024 on volume 2 of
AdvFS domain_1, use the following command: #
/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 [Toc] [Back]
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
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 filesets 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: nvbmtpg(8), nvlogpg(8), nvtagpg(8), vfilepg(8),
vsbmpg(8)
nvfragpg(8)
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