RESTORE(8)

NAME
restore - incremental file system restore

SYNOPSIS
/etc/restore key [ name ... ]

DESCRIPTION

Restore reads tapes dumped with the dump(8) command. Its actions are controlled by the key argument. The key is a string of characters containing at most one function letter and possibly one or more function modifiers. Other arguments to the command are file or directory names specifying the files that are to be restored. Unless the h key is specified (see below), the appearance of a directory name refers to the files and (recursively) subdirectories of that directory.

If the tape contains files or directories with '/' characters imbedded in them (note that this is illegal, but may occur if the filesystem is mounted over NFS on remote machines), restore will convert those names to '#inode_number#' for extraction. A list of the files renamed will be generated on stdout.

The function portion of the key is specified by one of the following letters:

r   The tape is read and loaded into the current directory. This should not be done lightly; the r key should only be used to restore a complete dump tape onto a clear file system or to restore an incremental dump tape after a full level zero restore. Thus

        /etc/newfs /dev/rzd0g m2344k
        /etc/mount /dev/zd0g /mnt
        cd /mnt
        restore r

    is a typical sequence to restore a complete dump. Another restore can be done to get an incremental dump in on top of this. Note that restore leaves a file restoresymtab in the root directory to pass information between incremental restore passes. This file should be removed when the last incremental tape has been restored.
    A dump(8) followed by a newfs(8) and a restore is used to change the size of a file system.

R   Restore requests a particular tape of a multi volume set on which to restart a full restore (see the r key above). This allows restore to be interrupted and then restarted.

x   The named files are extracted from the tape. If the named file matches a directory whose contents had been written onto the tape, and the h key is not specified, the directory is recursively extracted. The owner, modification time, and mode are restored (if possible). If no file argument is given, then the root directory is extracted, which results in the entire content of the tape being extracted, unless the h key has been specified.

t   The names of the specified files are listed if they occur on the tape. If no file argument is given, then the root directory is listed, which results in the entire content of the tape being listed, unless the h key has been specified. Note that the t key replaces the function of the old dumpdir program.

i   This mode allows interactive restoration of files from a dump tape. After reading in the directory information from the tape, restore provides a shell like interface that allows the user to move around the directory tree selecting files to be extracted. The available commands are given below; for those commands that require an argument, the default is the current directory.

    ls [arg] - List the current or specified directory. Entries that are directories are appended with a ``/''. Entries that have been marked for extraction are prepended with a ``*''. If the verbose key is set the inode number of each entry is also listed.

    cd arg - Change the current working directory to the specified argument.

    pwd - Print the full pathname of the current working directory.

    add [arg] - The current directory or specified argument is added to the list of files to be extracted. If a directory is specified, then it and all its descendents are added to the extraction list (unless the h key is specified on the command line). Files that are on the extraction list are prepended with a ``*'' when they are listed by ls.

    delete [arg] - The current directory or specified argument is deleted from the list of files to be extracted. If a directory is specified, then it and all its descendents are deleted from the extraction list (unless the h key is specified on the command line). The most expedient way to extract most of the files from a directory is to add the directory to the extraction list and then delete those files that are not needed.

    extract - All the files that are on the extraction list are extracted from the dump tape. Restore will ask which volume the user wishes to mount. The fastest way to extract a few files is to start with the last volume, and work towards the first volume.

    verbose - The sense of the v key is toggled. When set, the verbose key causes the ls command to list the inode numbers of all entries. It also causes restore to print out information about each file as it is extracted.

    help - List a summary of the available commands.

    quit - Restore immediately exits, even if the extraction list is not empty.

The following characters may be used in addition to the letter that selects the function desired.

v   Normally restore does its work silently. The v (verbose) key causes it to type the name of each file it treats preceded by its file type.

f   The next argument to restore is used as the name of the archive instead of /dev/rmt?. If the name of the file is ``-'', restore reads from standard input. Thus, dump(8) and restore can be used in a pipeline to dump and restore a file system with the command

        dump 0f - /usr | (cd /mnt; restore xf -)

y   Restore will not ask whether it should abort the restore if gets a tape error. It will always try to skip over the bad tape block(s) and continue as best it can.

m   Restore will extract by inode numbers rather than by file name. This is useful if only a few files are being extracted, and one wants to avoid regenerating the complete pathname to the file.

h   Restore extracts the actual directory, rather than the files that it references. This prevents hierarchical restoration of complete subtrees from the tape.

s   The next argument to restore is a number which selects the file on a multi-file dump tape. This allows multiple (short) dumps to reside on a single tape, separated by logical EOF marks. If not given, restore begins processing with the first information right after the physical BOT label.

b   The next argument to restore designates the blocksize (in 1024 byte units) to read the tape. This option is useful when performing restores where tape is an actual file in the filesystem or a streamer tape where the interface acts like a block interface. Restore attempts to intuit the blocksize by looking at the return from the first read of the tape. Dump(1) writes NTREC block records (currently 10) to normal density tapes unless given a different blocksize with the b option. Higher density tapes (such as 6250 bpi) are written with HIGHDENSITYTREC block records (currently 32).

DIAGNOSTICS
Complaints about bad key characters.

Complaints if it gets a read error. If y has been specified, or the user responds ``y'', restore will attempt to continue the restore.

If the dump extends over more than one tape, restore will ask the user to change tapes. If the x or i key has been specified, restore will also ask which volume the user wishes to mount. The fastest way to extract a few files is to start with the last volume, and work towards the first volume.

There are numerous consistency checks that can be listed by restore. Most checks are self-explanatory or can ``never happen''. Common errors are given below.

Converting to new file system format.
    A dump tape created from the old file system has been loaded. It is automatically converted to the new file system format.

<filename>: not found on tape
    The specified file name was listed in the tape directory, but was not found on the tape. This is caused by tape read errors while looking for the file, and from using a dump tape created on an active file system.

expected next file <inumber>, got <inumber>
    A file that was not listed in the directory showed up. This can occur when using a dump tape created on an active file system.

Incremental tape too low
    When doing incremental restore, a tape that was written before the previous incremental tape, or that has too low an incremental level has been loaded.

Incremental tape too high
    When doing incremental restore, a tape that does not begin its coverage where the previous incremental tape left off, or that has too high an incremental level has been loaded.

Tape read error while restoring <filename>
    Tape read error while skipping over inode <inumber>
    Tape read error while trying to resynchronize
    A tape read error has occurred. If a file name is specified, then its contents are probably partially wrong. If an inode is being skipped or the tape is trying to resynchronize, then no extracted files have been corrupted, though files may not be found on the tape.

resync restore, skipped <num> blocks
    After a tape read error, restore may have to resynchronize itself. This message lists the number of blocks that were skipped over.

    This error can also occur if the blocksize used to read the tape does not agree with the blocksize used to write it. This commonly occurs when tape is actually a file in the filesystem or a streamer tape where the write blocksize is not preserved. File damage has occurred if you see this message. Try using the b key with the correct blocksize to overcome this error.

FILES
/dev/rmt?    the default tape drive
/tmp/rstdir*    file containing directories on the tape.
/tmp/rstmode*    owner, mode, and time stamps for directories.
./restoresymtab    information passed between incremental restores.

SEE ALSO
rrestore(8C) dump(8), newfs(8), mount(8), mkfs(8)

BUGS
Restore can get confused when doing incremental restores from dump tapes that were made on active file systems.

A level zero dump must be done after a full restore. Because restore runs in user code, it has no control over inode allocation; thus a full restore must be done to get a new set of directories reflecting the new inode numbering, even though the contents of the files is unchanged.

When reading from tape, restore reads until it needs no more data, not until tape EOF. For multiple dumps saved on the same tape, you will need to advance the tape manually past the EOF marker after each restore is complete to get to the next dump (with ``mt fsf 1'').