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advfs(4)
NAME
advfs - A local file system and utilities
DESCRIPTION
The Advanced File System (AdvFS), the file system default on the Tru64 UNIX
operating system, features rapid crash recovery, high performance, and a
flexible structure that enables you to manage your file system while it is
on line. AdvFS is licensed with the Tru64 UNIX operating system.
A set of utilities that expands the capabilities of the AdvFS file system
is available as a separately licensed product: The AdvFS Utilities. These
utilities include capabilities such as adding volumes without reconfiguring
the directory hierarchy of the file system, cloning filesets to enable
online backup, improving system performance with domain balancing, and file
striping. A graphical user interface (GUI) that simplifies file system
management is available with the utilities.
Using journaling techniques, AdvFS provides faster crash recovery than the
UNIX File System (UFS), which implements crash recovery using the fsck
utility.
In addition to fast restarts, AdvFS ensures that file structures are
recovered consistently; extends file and fileset sizes to greater than 2
gigabytes; creates, deletes, and renames files faster than UFS; and
provides enhanced local and remote backup utilities (vdump and rvdump,
vrestore and rvrestore).
By configuring AdvFS as the root file system, the preceding AdvFS features
are extended to the root file system. You can configure the AdvFS as the
root file system during system installation.
A UFS file system corresponds to a disk partition and is, therefore,
limited by the size restrictions of that disk. In contrast, AdvFS filesets
can span all volumes in the file domain.
AdvFS File System Concepts
AdvFS introduces file system concepts that do not exist for UFS.
Understanding the following concepts prepares you for planning, creating,
and maintaining the AdvFS file system:
· Volumes
A volume is any mechanism that behaves like a UNIX block device, such
as a disk, disk partition, or logical volume that is configured with
the Logical Storage Manager (LSM).
· File Domain
A file domain is a named set of one or more volumes that provides a
shared storage pool for one or more filesets (see filesets below).
When you create a file domain using the mkfdmn command, you must
specify a domain name and one initial volume. The mkfdmn command
creates a subdirectory in the /etc/fdmns directory for each new file
domain. The file-domain subdirectory contains a symbolic link to the
initial volume.
If you have AdvFS Utilities, you can add additional volumes to an
existing file domain by using the addvol utility. With each added
volume, the addvol utility creates a new symbolic link in the
appropriate file-domain subdirectory of the /etc/fdmns directory.
· Filesets
A UFS file system has exclusive use of the volume that contains it; an
AdvFS fileset can be one of several in a domain that is composed of
one or more volumes.
An Advanced File System consists of a file domain with at least one
fileset that you create using the mkfset command. A fileset is a
mountable entity.
· Clone Fileset
A clone fileset is a read-only copy of an existing fileset, which you
can mount as you do other filesets. You create a clone fileset by
using the clonefset utility. The reason you create and mount a clone
fileset is to perform an online backup of the existing fileset.
A clone fileset is a snapshot of the original fileset, capturing and
fixing the original fileset at a moment in time. Any changes you make
to the original fileset will not appear in its clone. Changes to data
in files in the original fileset will not appear in the clone. Also,
files that you remove from the original fileset will remain accessible
in the clone under the names they had when you created the clone
fileset.
AdvFS Application Programming Interface
With the release of Tru64 UNIX Version 5.0, there is an application
programming interface (API) for AdvFS. Customers can use the API to build
customized backup and restore capabilities. The API consists of several
base system functions, which are described in the following reference
pages:
advfs_clonefset(3)
Create a read-only copy of an active fileset
advfs_get_fdmn_list(3)
Get an AdvFS file domain list
advfs_get_file_attributes(3)
Get the AdvFS attributes of a file
advfs_get_fset_list(3)
Obtain a list of all the filesets in an AdvFS file domain
advfs_get_fset_quotas(3)
Obtain fileset quotas for an AdvFS fileset
advfs_rmfset(3)
Remove a fileset or a clone fileset
advfs_set_file_attributes(3)
Set AdvFS file attributes
advfs_set_fset_quotas(3)
Set fileset quotas for an AdvFS fileset
AdvFS Commands in the Base System
The following list summarizes the AdvFS commands that are included in the
base system:
advfsstat
Displays file system statistics. See advfsstat(8).
advscan
Locates AdvFS partitions on disks. See advscan(8).
chfile
Changes the attributes of a file. See chfile(8).
chfsets
Changes the attributes of a fileset. See chfsets(8).
chvol
Changes the attributes of a volume. See chvol(8).
defragment
Makes the files in a file domain more contiguous. See defragment(8).
edquota
Edits the user or group quotas. See edquota(8).
mkfdmn
Creates a new file domain. See mkfdmn(8).
mkfset
Creates a fileset within an existing file domain. See mkfset(8).
mountlist
Checks for mounted AdvFS filesets. See mountlist(8).
ncheck
Creates a list of files on specified filesets, including the path names
and i-numbers. See ncheck(8).
nvbmtpg
Displays formatted BMT pages. See nvbmtpg(8).
nvfragpg
Displays formatted frag pages. See nvfragpg(8).
nvlogpg
Displays formatted log pages. See nvlogpg(8).
nvtagpg
Displays formatted tag pages. See nvtagpg(8).
quot
Summarizes fileset ownership. See quot(8).
quota
Displays disk usage and limits. See quota(1).
quotacheck
Checks file system quota consistency. See quotacheck(8).
quotaon
Turns on user and group quotas. See quotaon(8).
quotaoff
Turns off user and group quotas. See quotaoff(8).
renamefset
Renames an existing fileset. See renamefset(8).
repquota
Summarizes the disk usage and quotas for specified filesets. See
repquota(8).
rmfdmn
Removes an unused file domain from AdvFS. See rmfdmn(8).
rmfset
Deletes a fileset from a file domain. See rmfset(8).
shblk
Displays unformatted disk blocks. See shblk(8).
shfragbf
Displays frag file information. See shfragbf(8).
showfdmn
Displays domain attributes. See showfdmn(8).
showfile
Displays attributes for AdvFS files. See showfile(8).
showfsets
Displays information about the filesets in a domain. See showfsets(8).
switchlog
Moves the AdvFS log file to a different volume in a file domain. See
switchlog(8).
tag2name
Prints the path name of a file, given the tag number. See tag2name(8).
vbmtchain
Displays mcells that describe metadata for a file. See vbmtchain(8).
vbmtpg
Displays a formatted page of the bitfile metadata table (BMT). See
vbmtpg(8).
vdump
Backs up filesets. See vdump(8).
verify
Checks for and repairs file system inconsistencies. See verify(8).
vfile
Displays the contents of a file from an unmounted domain. See vfile(8).
vfragpg
Prints a single header page of a frag file. See vfragpg(8).
vlogpg
Displays a formatted page of the log. See vlogpg(8).
vlsnpg
Displays the logical sequence number (LSN) of a page of the log. See
vlsnpg(8).
vrestore
Restores files from devices written with the vdump command. See
vrestore(8).
vtagpg
Displays a formatted page of the tag directory. See vtagpg(8).
AdvFS Utilities
The AdvFS Utilities are licensed and purchased separately from the Tru64
UNIX operating system. However, the software and the reference pages for
them are installed when you install the base system. You must activate a
Product Authorization Key to activate the Advanced File System Utilities.
The following list summarizes the AdvFS Utilities commands:
addvol
Adds a volume to an existing file domain. See addvol(8).
advfsd
Starts the AdvFS graphical user interface (GUI) daemon.
balance
Balances the percentage of used space between volumes. See balance(8).
clonefset
Creates a read-only copy of a fileset. See clonefset(8).
dtadvfs
Starts the AdvFS graphical user interface. See dtadvfs(8).
migrate
Moves the location of a file within a file domain. See migrate(8).
mktrashcan
Attaches directories to a trashcan directory, which stores deleted
files. See mktrashcan(1).
rmtrashcan
Detaches a specified directory from a trashcan directory. See
mktrashcan(1).
rmvol
Removes a volume from an existing file domain. See rmvol(8).
shtrashcan
Shows the trashcan directory, if any, that is attached to a specified
directory. See mktrashcan(1).
stripe
Interleaves storage allocation of a file across two or more volumes
within a file domain. See stripe(8).
RESTRICTION
When configuring root on AdvFS, set up one partition and one fileset in the
file domain. Multiple volumes are not supported on root (except for a
cluster root).
EXAMPLE
The following example creates a file domain called accounts_dmn, which
contains dsk1c as the initial volume. The example also creates two
filesets, credit_fs and debit_fs, and mounts both filesets.
# mkfdmn /dev/disk/dsk1c accounts_dmn
# mkfset accounts_dmn credit_fs
# mkfset accounts_dmn debit_fs
# mkdir /mnt/credit /mnt/debit
# mount -t advfs accounts_dmn#credit_fs /mnt/credit
# mount -t advfs accounts_dmn#debit_fs /mnt/debit
SEE ALSO
Commands: mkdir(1) ,fdmns(4), mkfdmn(8), mkfset(8), mount(8)
Files: advfs_err(4)
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