frecover(1M)frecover(1M)NAMEfrecover - selectively recover files
SYNOPSIS
config] device] skip] extarg]
device]
config] path] device] graph] path] skip] extarg]
device] config]
device] config]
Remarks
Note: The and commands are deprecated for creating new archives. See
for more information.
DESCRIPTION
reads media written by the command. Its actions are controlled by the
selected function or
The function performed by is specified by one of the following options:
The backup media is read and the contents are loaded
into the directories from which they were backed up. This
option should only be used to recover a complete backup
onto a clear directory or to recover an incremental backup
after a full level-zero recovery (see fbackup(1M)). This
is the default behavior.
The files identified by the
and options (see below) are extracted or not extracted from
the backup media. If a file to be extracted matches a
directory whose contents have been written to the backup
media, and the option is not specified, the directory is
recursively extracted. The owner, modification time, and
access control list (including optional entries, unless the
option is specified) are recovered. If no file argument is
given (including an empty graph file), all files on the
backup media are extracted, unless the option is specified.
The index on the current volume is extracted
from the backup media and is written to path.
The volume header on the current volume
is extracted from the backup media and is written to path.
The following fields from the header are extracted in the
format label:value with one pair per line.
On valid media, it contains the value
(HP-UX 11i Version 3 and
beyond). Previous values of
this field were (between HP-UX
10.20 and HP-UX 11i Version 2
inclusive) and (before HP-UX
10.20).
This field contains the result of
This field contains the result of
This field contains the result of
This field contains the result of
This field contains the result of
This field contains the maximum length in bytes of a data
record.
This field contains the time
was started.
This field contains the number of times
the media has been used for
backup.
This field contains a character followed by 3 digits,
and identifies the current vol‐
ume in the backup.
This field contains the number of data records between
checkpoints.
This field contains the number of files between
for backups made with DDS tape
drives.
This field contains the size of the index.
This field is composed of 2 items: the process
ID (pid), and the start time of
that process.
This field contains the language used to make the backup.
An interrupted full recovery can be continued using this option.
uses the information in file path to continue the recovery
from where it was interrupted. The only command line
option used by with this option is The values in path over‐
ride all other options to Note also that only full recover‐
ies are restarted with this option, because no history of
include or exclude lists is stored in the restart file. If
a partial recovery (i.e., using the option) is interrupted
then restarted with this option, continues recovering where
the partial recovery left off, but restores all files on
the backup media beyond this point.
The following options can be used in addition to the option above that
selects the desired function:
config specifies the name of a configuration file to be used to
alter the behavior of The configuration file allows the
user to specify the action to be taken on all errors, the
maximum number of attempts at resynchronizing on media
errors option), and the action to be taken on media errors.
Each entry of a configuration file consists of an action
identifier followed by a separator followed by the speci‐
fied action. Valid action identifiers are and Separators
can be either tabs or spaces. In the following sample con‐
figuration file, each time an error is encountered, the
script is executed. The script is executed each time the
backup media is to be changed. The maximum number of
resynchronization attempts is five.
path is interpreted as a graph to be excluded from the recovery.
There is no limit on how many times the option can be spec‐
ified.
device identifies the backup device to be used instead of the
default or on systems where legacy Device Special Files
(DSF) is disabled. If device is reads from standard input.
Thus and can be used in a pipeline to backup and recover a
file system as follows:
If more than one output file is specified, uses each one
successively and then repeats in a cyclical pattern. Pat‐
terns can be used in the device name in a way similar to
file name expansion as done by The expansion of the pattern
results in all matching names being in the list of devices
used. A device on the remote machine can be specified in
the form creates a server process, on the remote machine to
access the tape device. If does not exist on the remote
system, creates a server process from on the remote machine
to access the tape device. The pattern matching capability
does not apply to remote devices. Only raw magnetic tapes
can be remote devices. The capability is not used when
accessing remote DDS devices.
graph defines a graph file. Graph files are text files and con‐
tain the list of file names (graphs) to be recovered or
skipped. Files are recovered using the option; so, for
example, if the user wants to recover all of the graph file
contains one entry:
It is also possible to skip files by using the option. For
example, if a user wants to recover all of except for the
subgraph the graph file contains two entries:
If the graph file is missing, exits with an error message.
An empty graph file results in recovering all files on the
media.
Extract the actual directory, rather than the files that it references.
This prevents hierarchical restoration of complete subtrees
from the backup media.
path is interpreted as a graph to be included in the recovery.
There is no limit on how many times the option can be spec‐
ified.
Print a message each time a file marker is encountered.
Using this option, prints a message each time either a DDS
a filemark (EOF), or a checkpoint record is read. Although
useful primarily for troubleshooting, these messages can
also be used to reassure the user that the backup is pro‐
gressing during long, and otherwise silent, periods during
the recovery.
Recover the file from the backup media irrespective of age.
Normally does not overwrite an existing file with an older
version of the file.
Attempt to optimize disk usage by not writing
null blocks of data to sparse files.
Normally works silently. Verbose option. Displays the file type
and name of each file processed.
Automatically answer
to any inquiries.
Do not recover any optional entries in access control lists
(ACLs). Normally, all access control information, includ‐
ing optional ACL entries, is recovered. This option drops
any optional entries and sets the permissions of the recov‐
ered file to the permissions of the backed up file. Use
this option when recovering files backed up from a system
with ACLs on a system where ACLs are not present (see
acl(5)).
Recover files without recovering leading directories.
For example, this option would be used if a user wants to
recover and to a local directory without creating each of
the graph structures.
Specifies the handling of any extent attributes backed up by
The option takes the following keywords as arguments:
Issue a warning message if extent attributes cannot
be restored, but restore the file anyway.
Do not restore extent attributes.
Issue an error message and do not restore the file
if extent attributes cannot be restored.
Extent attributes cannot be restored if the files
are being restored to a file system which does
not support extent attributes or if the file sys‐
tem's block size is incompatible with the extent
attributes. If is not specified, extarg defaults
to
(no recovery)
Prevent from actually recovering any files onto disk, but
read the backup as if it was, in fact, recovering the data
from the backup, producing the same output that it would on
a normal recovery. This option is useful for verifying
backup media contents in terms of validity (block checksum
errors are reported), and contents (a listing of files can
be produced by using the and options together). Note that
the listing of files produced with the and options requires
the reading of the entire backup, but is therefore a more
accurate reflection of the backup's contents than the index
stored at the beginning of the backup (which was created at
the start of the backup session, and is not changed during
the course of the backup).
Use the effective uid and gid for the owner and group
of the recovered file instead of the values on the backup
media.
does not ask whether it should abort the recovery
if it gets a media error. It tries to skip the bad block
or blocks and continue. Residual or lost data is written
to the file named by skip. The user can then edit this
file and recover otherwise irretrievable data.
Recover files relative to the current working directory.
Normally recovers files to their absolute path name.
EXTERNAL INFLUENCES
Environment Variables
determines the order in which expects files to be stored on the backup
device and the order in which file names are output by the option.
determines the language in which messages are displayed.
If and are not specified in the environment or are set to the empty
string, the value of is used as a default for each unspecified or empty
variable. If is not specified or is set to the empty string, a default
of "C" (see lang(5)) is used instead of If any internationalization
variable contains an invalid setting, behaves as if all international‐
ization variables are set to "C". See environ(5).
International Code Set Support
Single- and multi-byte character code sets are supported.
WARNINGS
The and commands are deprecated for creating new archives. In a future
HP-UX release, creation of new archives with these commands will not be
supported. Support will be continued for archive retrieval. Use the
standard command (portable archive interchange) to create archives.
See pax(1).
For incremental backups created prior to installing HP-UX Release 8.0,
or for recoveries that do not begin with the first volume (such as when
reading tape 3 first), it is possible for the preceding directories to
a recoverable file to not be on the media. This can happen, for exam‐
ple, if the directories did not change since the last full backup. If
encounters a file on the backup that should be recovered, but it has
not recovered the file's parent directories from the backup, it prints
a message stating that the recovery will continue with that file, and
attempts to create the file's parent directories as needed.
Use of does not require special privileges. However, if a user does
not have access permission to a given file, the file is not recovered.
In HP-UX 11i Version 3, the maximum value for fields returned from was
increased (from 8 to 256). To accommodate the larger size, a format
change was necessary. A new magic number, was created to distinguish
this new format.
Likewise with HP-UX 10.20, HP-UX added support for large files (greater
than 2GB) and increased UID/GIDs (greater than 60,000). The magic num‐
ber associated with this release through HP-UX 11i Version 2 (inclu‐
sive) is
Archives and files with formats and attributes that are unsupported on
previous HP-UX releases could cause severe problems or unpredictable
behavior if attempts were made to restore onto these systems. For this
reason, creates tapes with a magic number that is only recognized on
releases which support the features and format being archived. This
prevents tape archives from being restored on earlier HP-UX systems
than are supported. still reads all tape formats so that tape archives
created on earlier HP-UX systems can be restored.
The index format now includes the file size in the first field; the
previous format simply had the '#' character in that field. The imple‐
mentation provides both forward and backward compatibility between the
old and new index formats. However, the file sizes are used in con‐
junction with the checkpoints to increase selective recovery speed on
DLT devices, so recovery of an volume that does not have the new index
format will not see that performance gain.
When using a DDS tape written with the current release of to do a par‐
tial recovery, attempts to use the DDS fast-search capability to find
files on the tape more quickly. In order to do this, however, needs to
create an in-memory copy of the index, and mark the files on that index
which it needs to recover before actually reading through the tape to
find the files. This is done when the first index is read from the
tape, and accounts for a period of time just after recovery is begun
where the tape is inactive while this in-memory index is constructed.
The larger the index is, the longer this period lasts.
The utility set comprised of and was originally designed for use on
systems equipped with not more than one gigabyte of total file system
storage. Although the utilities have no programming limitations that
restrict users to this size, complete backups and recoveries of sub‐
stantially larger systems can cause a large amount of system activity
due to the amount of virtual memory (swap space) used to store the
indices. Users who want to use these utilities, but are noticing poor
system-wide performance due to the size of the backup, are encouraged
to back up their systems in multiple smaller sessions, rather than
attempting to back up the entire system at one time. However, if the
entire backup must be done with a single session, the user may
encounter an error in if there is not enough virtual memory available.
If this happens, the user might consider adjusting the maxdsiz parame‐
ter or the swap space; both of these require a reboot.
Note that when recovering files with access control lists, the ACL
entries are stored on the backup as user login names. If a login name
cannot be found in the password file, the file is recovered without its
ACL, and an error is printed. In order to fully recover files backed
up with ACLs, the password file must be recovered before attempting to
recover any desired ACLs.
Network special files are obsolete. Therefore, cannot restore these
files. A warning message is issued if an attempt is made to recover a
network special file, and the file is skipped.
Care should be taken to match the names specified by the include and
exclude options with the names in the index on the tape. Since the
files are stored on the backup in lexographic order as defined by the
or environment variable, uses the exact path names to determine when a
partial recovery is complete, and when an earlier tape needs to be
loaded. If a user's specification of a file to be recovered is mis‐
spelled, this may cause confusing messages, such as asking for the pre‐
vious volume, when volume one is mounted.
DEPENDENCIES
does not support QIC-120 and QIC-150 formats on QIC devices. If is
attempted for these formats, fails and the following message is dis‐
played :
AUTHOR
was developed by HP.
FILES
Default backup device.
Default backup device if legacy DSF is disabled.
SEE ALSOcpio(1), pax(1), dump(1M), fbackup(1M), restore(1M), rmt(1M), acl(5).
TO BE OBSOLETED frecover(1M)
