nvfragpg(8) System Manager's Manual 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
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 util-
ity. Display the frag file free list. Display all the data in a frag file.
OPERANDS
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. 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 fileset's tag number, -T fileset_tag.
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 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 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 fol-
lowing 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 logical block number 1024 on volume 2 of AdvFS domain_1, use the fol-
lowing 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
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 com-
mand: # /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 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: nvbmtpg(8), nvlogpg(8), nvtagpg(8), vfilepg(8), vsbmpg(8)
nvfragpg(8)