advfs(4) — File Formats

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 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).

•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

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 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 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 domain more contiguous. See defragment(8).

edquota
Edits the user or group quotas. See edquota(8).

fixfdmn
Checks and repairs corrupted AdvFS domains. See fixfdmn(8).

mkfdmn
Creates a new domain. See mkfdmn(8).

mkfset
Creates a fileset within an existing 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).

quotaoff
Turns off user and group quotas. See quotaoff(8).

quotaon
Turns on user and group quotas. See quotaon(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 domain from AdvFS. See rmfdmn(8).

rmfset
Deletes a fileset from a domain. See rmfset(8).

salvage
Recovers file data from damaged AdvFS domains. See salvage(8).

savemeta
Takes a snapshot of an AdvFS domain’s metadata. See savemeta(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 domain. See switchlog(8).

tag2name
Prints the path name of a file, given the tag number. See tag2name(8).

vdfDisplays disk information for AdvFS domains and filesets. See vdf(8).

vdump
Backs up filesets. See vdump(8).

verify
Checks for and repairs file system inconsistencies. See verify(8).

vfilepg
Displays pages of an AdvFS file. See verify(8).

vrestore
Restores files from devices written with the vdump command. See vrestore(8).

vsbmpg
Displays a page from a storage bitmap (SBM) file. See verify(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.

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:

addvol
Adds a volume to an existing 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).

dmapi
Accesses the Data Management Applications Programming Interface (DMAPI). See dmapi(3).

dtadvfs
Starts the AdvFS graphical user interface. See dtadvfs(8).

lsmsa
Runs the Logical Storage Manager Storage Administrator (LSMSA). See lsmsa(8).

migrate
Moves the location of a file within a 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 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 domain. See stripe(8).

RESTRICTION

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).

EXAMPLE

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

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