nvfragpg(8)nvfragpg(8)NAMEnvfragpg - Displays 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 [-v] [-f] volume_id -b block
/sbin/advfs/nvfragpg 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 utility.
Displays the frag file free list. Displays 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 fol‐
lowing 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 argu‐
ment 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.
DESCRIPTION
Use the nvfragpg utility to display information about frag file meta‐
data.
Each fileset in an AdvFS domain has one frag file. Frag files are col‐
lections of file fragments. The file fragments in a frag file are
grouped together by file fragment size into 16-page groups. File frag‐
ments 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
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
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 file‐
set_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 multi‐
ple 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 inter‐
pret 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 file‐
sets 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 con‐
secutive 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 filesets 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)