datio(1)

NAME

datio − backup to and restore files from DAT tape devices

SYNOPSIS

datio −o [aAxvh] DATdev [DATdev [DATdev [DATdev]]]

datio −i [tuxvmU] [pattern] DATdev

DESCRIPTION

datio is designed to both simplify and optimize routine file backup and recovery to a Digital Audio Tape (DAT) device. It combines the standard format of the cpio utility, with a simple to use, extremely fast recovery strategy. datio provides significant enhancements to file restore in addition to an interactive front-end for simplified file recovery.

datio −o (copy out) Read the standard input to obtain a list of file names and path names and archive those files to up to four separate DAT drives using the cpio(1) format.

datio −i (copy in) Restore file(s) from DATdev which is assumed to have been created with datio −o. Only files with names that match pattern, according to the rules of Pattern Matching Notation (see regexp(5)), are selected. Only one pattern can be specified. If no pattern is specified, datio enters INTERACTIVE mode, which allows the user to interactively restore file(s). Extracted files are conditionally created and copied into the current directory tree, as determined by the options described below. The permissions of the files match the permissions of the original files when the archive was created by datio −o unless the −U option is used. Any directories are created as required. File owner and group are that of the current user unless the user has appropriate privileges, in which case datio retains the owner and group of the files of the previous datio −o.

In both cases, DATdev must refer to a character special file associated with a DAT device. The device must specify the no-rewind and the Berkeley style mode flags ( see mt(7) ).

datio can create a single archive split over multiple tapes in up to 4 DAT drives. Thus appends are not allowed. During writing, a cpio archive is written to the tape(s). Following the archive, on the last tape, a table of contents (TOC) for the archive is written to the tape. During input operations, the TOC is retrieved to enhance the file restore process. Under favorable conditions, a file can be restored from any position on any tape in the archive set within a few minutes.

During output, datio allows up to four DAT drives to be specified on the command line. These drives are written to sequentially by the program. If datio runs out of tapes, it will prompt the user to enter a new tape device. The user should insert a new tape into a drive, allow it to come online and enter it’s device file path. When the archive is completed, all tapes used should be labeled and numbered, so that the correct tape can be inserted on a file recovery operation. Note that datio needs the whole set of tapes in oder to work correctly.

datio prompts the user to insert archive tapes into the specified drive. The last tape of the backup set should be inserted first so that the TOC can be retrieved. The user will then be asked to insert other tapes as required.

For the majority of backup and recovery work required by small to medium size systems, datio can be used without any knowledge of the cpio command. However, specialized applications may require alternative strategies. (See cpio Compatibility below.)

Options

datio recognizes the following options in addition to −i and −o:

a Reset access times of input files after they are copied to current time.

A Suppress warning messages regarding optional access control list entries. datio (1) does not backup optional access control list entries in a file’s access control list (see acl(5)). Normally, a warning message is printed for each file that has optional access control list entries.

t Print only a table of contents of the archive. No files are created, read, or copied.

u Copy unconditionally (normally, an older file does not replace a newer file with the same name).

x Save or restore device special files. Since mknod(2) is used to recreate these files on a restore, −ix can only be used by users with appropriate privileges. This option is not intended for file transfer between different systems, only for backup of a single system. Restoring device files onto a different system can be very dangerous.

v Verbose causes a list of file names to be printed. When used with the t option, the table of contents looks similar to the output of an ls −l command (see ls(1)).

m Retain previous file modification time. This option does not affect directories that are being copied.

h Follow symbolic links as though they were normal files or directories. Normally, datio archives the link.

U Use the process’s file-mode creation mask (see umask(2)) to modify the mode of files created, in the same manner as creat(2).

If you want to pass one or more metacharacters to datio without the shell expanding them, be sure to precede each of them with a backslash (\).

Device files written with the −ox option (such as /dev/tty03) do not transport to other implementations of HP-UX.

cpio Compatibility

datio uses the same archive format as cpio(1) with the options: −oBc . The −oB causes all tape records to be 5120-bytes long. The −c option aids portability to non-HP machines, and is now a requirement for POSIX-conformance.

Certain applications may require the user to use cpio directly. For instance, if it is necessary to move an archive between HP and non-HP architectures (where byte alignment is different such as to VAX or PDP-11 systems), it is recommended using the cpio command directly.

DIAGNOSTICS

The diagnostic message "Out of phase" indicates that datio could not successfully read the particular "magic number" for cpio in the header. We assume the archive is corrupt (or the drive is faulty), and any further work should use cpio. (See the −iR option: resynchronize.)

EXAMPLES

The first example below copies the present directories subtree (files and subdirectories) , into an archive; the second restores the directory x25 and all files contained in it.

find . −print │ datio −o /dev/rmt/0mn

cd x25
datio −i ’x25/*’ /dev/rmt/0mn

File restore is made significantly easier using the INTERACTIVE mode of datio . It is entered by either not specifying a pattern (on the command line during input), or entering a pattern that cannot be matched:

datio −i /dev/rmt/0m

datio will prompt you with a menu.

WARNINGS

Path names are restricted to 256 characters. If there are too many unique linked files, the program runs out of memory to keep track of them. Thereafter, linking information is lost. Only users with appropriate privileges can copy special (device) files. If the file to be restored has a space character in the pathname, then wildcards must be used to restore the file.

datio tapes written on HP machines with the −ox options can sometimes mislead (non-HP) versions of cpio that do not support the −x option. If a non-HP (and non-AT&T) version of cpio happens to be modified so that (HP) cpio recognizes it as a device special file, a spurious device file might be created.

If /dev/tty is not accessible, datio issues a complaint and exits.

datio does not make empty directories.

POSIX defines a file named TRAILER!!! as an end-of-archive marker. Consequently, if a file of that name is contained in a group of files being written by datio −i, the file is interpreted as end-of-archive, and no remaining files are copied. Recommended practice is to avoid naming files anything that resembles an end-of-archive file name.

All datio archives are written using the −c option of cpio to conform with POSIX

If the user does not have appropriate privileges, the −U option must also be used to get POSIX-conforming behavior when reading an archive. Users with appropriate privileges should not use this option to get POSIX-conforming behavior.

Access Control Lists

Access control list descriptions in this entry apply only to standard HP-UX operating systems. If HP-UX BLS software has been installed, access control lists are handled differently. Refer to HP-UX BLS documentation for information about access control lists in the HP-UX BLS environment.

AUTHOR

datio was developed by HP.

Museum

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