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advfs(4)
NAME
advfs - A local file system and utilities
DESCRIPTION
The File System (AdvFS), a file system option on the DIGITAL 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.
The AdvFS component is licensed with the DIGITAL UNIX operating system and
is available as file system option during installation.
A set of utilities that expands the capabilities of the AdvFS file system
is available: The Advanced File System Utilities. These utilities include
capabilities such as adding volumes without reconfiguring the directory
hierarchy of the file system, cloning filesets to enable online backup, and
improving system performance with domain balancing, and file striping.
Additionally, a graphical user interface (GUI) that simplifies file system
management is available with the utilities. The Advanced File System
Utilities component is licensed separately from the DIGITAL UNIX operating
system.
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 backup utilities (vdump and vrestore).
By configuring AdvFS as the root filesystem, the preceding AdvFS features
are extended to the root filesystem.
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 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.
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
fdmns directory.
· Filesets
A fileset is both the logical file structure that the user recognizes
and a unit that you can mount. Whereas you typically mount an entire
UNIX file system, with the AdvFS you mount the individual filesets of
a file domain.
An Advanced File System consists of a file domain with at least one
fileset that you create using the mkfset command. For each fileset,
the mkfset command creates a .tags directory. The .tags directory is a
permanent directory that is reserved for future use. You cannot
delete, rename, or add any files to the .tags directory.
· 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. For instance,
new files added to the original fileset will not appear in the 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.
The following list summarizes the AdvFS commands:
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).
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 files in an Advanced File System. 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).
Note
Operations supported by the following AdvFS commands will be
retired in a future release of the DIGITAL UNIX operating system
and are supported only for backward compatibility with operating
system versions earlier than DIGITAL UNIX Version 4.0:
vedquota(8), vncheck(8), vquot(8), vquota(1), vquotaon(8),
vquotaoff(8), and vrepquota(8). The operations supported by
these retiring commands are also supported by the following
commands edquota(8), ncheck(8), quot(8), quota(1), quotaon(8),
quotaoff(8), and repquota(8).
The Advanced File System Utilities are licensed separately from the DIGITAL
UNIX operating system and must be purchased separately. Both the software
and the reference pages are contained in the separately-licensed product,
and must be installed before being used. The following list summarizes the
Advanced File System 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(8).
rmtrashcan
Detaches a specified directory from a trashcan directory. See
mktrashcan(8).
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(8).
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.
EXAMPLE
The following example creates a file domain called accounts_dmn, which
contains rz1c as the initial volume. The example also creates two filesets,
credit_fs and debit_fs and mounts both filesets.
# mkfdmn /dev/rz1c 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
RELATED INFORMATION
advfs_err(4), fdmns(4), mkfdmn(8), mkfset(8), mkdir(1), mount(8).