advfs - A local file system and utilities
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
domain.
AdvFS File System Concepts [Toc] [Back]
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). Domain
A 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 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 domain. The
domain subdirectory contains a symbolic link to the
initial volume.
If you have AdvFS Utilities, you can add additional
volumes to an existing domain by using the addvol
utility. With each added volume, the addvol utility
creates a new symbolic link in the appropriate
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 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 [Toc] [Back]
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: Create a read-only copy of an active
fileset Get an AdvFS domain list Get the AdvFS attributes
of a file Obtain a list of all the filesets in an AdvFS
domain Obtain fileset quotas for an AdvFS fileset Remove a
fileset or a clone fileset Set AdvFS file attributes Set
fileset quotas for an AdvFS fileset
AdvFS Commands in the Base System [Toc] [Back]
The following list summarizes the AdvFS commands that are
included in the base system: Displays file system statistics.
See advfsstat(8). Locates AdvFS partitions on
disks. See advscan(8). Changes the attributes of a file.
See chfile(8). Changes the attributes of a fileset. See
chfsets(8). Changes the attributes of a volume. See
chvol(8). Makes the files in a domain more contiguous.
See defragment(8). Edits the user or group quotas. See
edquota(8). Checks and repairs corrupted AdvFS domains.
See fixfdmn(8). Creates a new domain. See mkfdmn(8).
Creates a fileset within an existing domain. See mkfset(8). Checks for mounted AdvFS filesets. See
mountlist(8). Creates a list of files on specified filesets,
including the path names and i-numbers. See
ncheck(8). Displays formatted BMT pages. See nvbmtpg(8).
Displays formatted frag pages. See nvfragpg(8). Displays
formatted log pages. See nvlogpg(8). Displays formatted
tag pages. See nvtagpg(8). Summarizes fileset ownership.
See quot(8). Displays disk usage and limits. See
quota(1). Checks file system quota consistency. See quotacheck(8). Turns off user and group quotas. See quotaoff(8). Turns on user and group quotas. See quotaon(8). Renames an existing fileset. See renamefset(8).
Summarizes the disk usage and quotas for specified filesets.
See repquota(8). Removes an unused domain from
AdvFS. See rmfdmn(8). Deletes a fileset from a domain.
See rmfset(8). Recovers file data from damaged AdvFS
domains. See salvage(8). Takes a snapshot of an AdvFS
domain's metadata. See savemeta(8). Displays unformatted
disk blocks. See shblk(8). Displays frag file information.
See shfragbf(8). Displays domain attributes. See
showfdmn(8). Displays attributes for AdvFS files. See
showfile(8). Displays information about the filesets in a
domain. See showfsets(8). Moves the AdvFS log file to a
different volume in a domain. See switchlog(8). Prints
the path name of a file, given the tag number. See
tag2name(8). Displays disk information for AdvFS domains
and filesets. See vdf(8). Backs up filesets. See
vdump(8). Checks for and repairs file system inconsistencies.
See verify(8). Displays pages of an AdvFS file. See
verify(8). Restores files from devices written with the
vdump command. See vrestore(8). Displays a page from a
storage bitmap (SBM) file. See verify(8).
AdvFS Utilities [Toc] [Back]
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.
Also available with the AdvFS Advanced Utilities license
is support for data management applications through the
Data Management Applications Programming Interface
(DMAPI). See the DMAPI manpage for details.
The following list summarizes the AdvFS Utilities commands:
Adds a volume to an existing domain. See addvol(8).
Starts the AdvFS graphical user interface (GUI) daemon.
Balances the percentage of used space between volumes. See
balance(8). Creates a read-only copy of a fileset. See
clonefset(8). Accesses the Data Management Applications
Programming Interface (DMAPI). See dmapi(3). Starts the
AdvFS graphical user interface. See dtadvfs(8). Runs the
Logical Storage Manager Storage Administrator (LSMSA).
See lsmsa(8). Moves the location of a file within a
domain. See migrate(8). Attaches directories to a trashcan
directory, which stores deleted files. See mktrashcan(1). Detaches a specified directory from a trashcan
directory. See mktrashcan(1). Removes a volume from an
existing domain. See rmvol(8). Shows the trashcan directory,
if any, that is attached to a specified directory.
See mktrashcan(1). Interleaves storage allocation of a
file across two or more volumes within a domain. See
stripe(8).
When configuring root on AdvFS, set up one partition and
one fileset in the domain. Multiple volumes are not supported
on root (except for a cluster root).
The following example creates a domain called
accounts_dmn, which contains dsk1c as the initial volume.
The example also creates two filesets, credit_fs and
debit_fs, creates mount point directories, 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
Commands: mkdir(1), mkfdmn(8), mkfset(8), mount(8),
showfdmn(8), showfsets(8), showfile(8)
Functions: dmapi(3)
Files: advfs_err(4), fdmns(4)
advfs(4)
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