advfs(4) Kernel Interfaces Manual 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 perfor-
mance, 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 Utili-
ties. 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 config-
ured 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 com-
posed 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 file-
set.
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: Create a read-only copy of an active fileset Get an AdvFS file domain list Get the AdvFS attributes of a file Obtain a
list of all the filesets in an AdvFS file 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
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 file domain more contiguous. See defragment(8).
Edits the user or group quotas. See edquota(8). Creates a new file domain. See mkfdmn(8). Creates a fileset within an existing file
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 on user and group quotas.
See quotaon(8). Turns off user and group quotas. See quotaoff(8). Renames an existing fileset. See renamefset(8). Summarizes the disk
usage and quotas for specified filesets. See repquota(8). Removes an unused file domain from AdvFS. See rmfdmn(8). Deletes a fileset
from a file domain. See rmfset(8). Displays unformatted disk blocks. See shblk(8). Displays frag file information. See shfragbf(8). Dis-
plays 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 file domain. See switchlog(8). Prints the path name of
a file, given the tag number. See tag2name(8). Displays mcells that describe metadata for a file. See vbmtchain(8). Displays a formatted
page of the bitfile metadata table (BMT). See vbmtpg(8). Backs up filesets. See vdump(8). Checks for and repairs file system inconsisten-
cies. See verify(8). Displays the contents of a file from an unmounted domain. See vfile(8). Prints a single header page of a frag file.
See vfragpg(8). Displays a formatted page of the log. See vlogpg(8). Displays the logical sequence number (LSN) of a page of the log. See
vlsnpg(8). Restores files from devices written with the vdump command. See vrestore(8). 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: Adds a volume to an existing file 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). Starts the AdvFS graphical user interface. See dtadvfs(8). Moves the location of a file
within a file 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 file 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 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)
advfs(4)