NAME

advfs − A local file system and utilities

DESCRIPTION

The POLYCENTER Advanced File System (AdvFS) is a file system option on the DEC OSF/1 operating system.  The Advanced File System provides rapid crash recovery, high performance, and a flexible structure that enables you to manage your file system while it is on line. 

An optional set of utilities is available for AdvFS that expands the capabilities of the file system.  The POLYCENTER Advanced File System Utilities provide functions such as adding volumes without reconfiguring the directory hierarchy of the file system, cloning filesets, and improving system performance with file defragmentation, domain balancing, and file striping. A graphical user interface (GUI) that simplifies file system management is available With the AdvFS Utilities. 

The Advanced File System component is licensed with the DEC OSF/1 operating system and is available as an optional subset during installation.  The POLYCENTER Advanced File System Utilities is available as a separately licensed layered product. 

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, these AdvFS features are extended to the root filesystem. 

AdvFS introduces file system concepts that do not exist for the UNIX file system. Understanding the following concepts prepares you for planning, creating, and maintaining the Advanced File System:

       •Volumes A volume is any mechanism that behaves like a UNIX block device, such as a logical volume that is configured with the Logical Storage Manager (LSM), or a disk partition.

       •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 a whole UNIX file system, with the Advanced File System 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.

A UNIX 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. 

The POLYCENTER Advanced File System (AdvFS) is licensed with the DEC OSF/1 operating system. The following list describes AdvFS commands:

chfileChanges the attributes of a file. See chfile(8). 

chfsetsChanges the attributes of a fileset.  See chfsets(8). 

chvolChanges the attributes of a volume. See chvol(8). 

mkfdmnCreates a new file domain. See mkfdmn(8). 

mkfsetCreates a fileset within an existing file domain. See mkfset(8). 

renamefsetRenames an existing fileset.  See renamefset(8). 

rmfsetDeletes a fileset from a file domain. See rmfset(8). 

rmvolRemoves a volume from an existing file domain.  See rmvol(8). 

showfdmnDisplays domain attributes. See showfdmn(8). 

showfileDisplays attributes for files in an Advanced File System. See showfile(8). 

showfsetsDisplays information about the filesets in a domain. See showfsets(8). 

vdumpBacks up filesets.  See vdump(8). 

vedquotaEdits the user or group quotas.  See vedquota(8). 

vncheckCreates a list of files on specified filesets, including the path names and i-numbers.  See vncheck(8). 

vquotSummarizes fileset ownership.  See vquot(8). 

vquotaDisplays disk usage and limits.  See vquota(1). 

vquotaonTurns on user and group quotas.  See vquotaon(8). 

vquotaoffTurns off user and group quotas.  See vquotaoff(8). 

vrepquotaSummarizes the disk usage and quotas for specified filesets.  See vrepquota(8). 

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

The POLYCENTER Advanced File System Utilities are licensed separately from the base file system and must be purchased separately.  They are contained on the DEC Layered Products CDROM.  The following list describes the POLYCENTER Advanced File System Utilities:

addvolAdds a volume to an existing file domain. See addvol(8). 

balanceBalances the percentage of used space between volumes. See balance(8). 

clonefsetCreates a read-only copy of a fileset. See clonefset(8). 

defragmentMakes the files in a file domain more contiguous. See defragment(8). 

dxadvfsStarts the AdvFS graphical user interface.  See dxadvfs(8). 

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

mktrashcanAttaches directories to a trashcan directory, which stores deleted files.  See mktrashcan(8). 

rmtrashcanDetaches a specified directory from a trashcan directory. See mktrashcan(8). 

rmfdmnRemoves an unused file domain from AdvFS. See rmfdmn(8). 

rmvolRemoves a volume from an existing file domain. See rmvol(8). 

shtrashcanShows the trashcan directory, if any, that is attached to a specified directory. See mktrashcan(8). 

stripeInterleaves 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).