Jump to content United States-English
HP.com Home Products and Services Support and Drivers Solutions How to Buy
» Contact HP
More options
HP.com home
HP-UX Reference > F


HP-UX 11i Version 3: February 2007

Technical documentation

» Feedback
Content starts here

 » Table of Contents

 » Index


frecover — selectively recover files


/usr/sbin/frecover -r [-hmosvyAFNOX] [-c config] [-f device] [-S skip] [-E extarg]

/usr/sbin/frecover -R path [-f device]

/usr/sbin/frecover -x [-hmosvyAFNOX] [-c config] [-e path] [-f device] [-g graph] [-i path] [-S skip] [-E extarg]

/usr/sbin/frecover -I path [-vy] [-f device] [-c config]

/usr/sbin/frecover -V path [-vy] [-f device] [-c config]


Note: The fbackup, frecover, and ftio commands are deprecated for creating new archives. See WARNINGS for more information.


frecover reads media written by the fbackup command. Its actions are controlled by the selected function -r, -R, -x, -V, or -I.

The function performed by frecover 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 -i, -e, and -g 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 -h option is not specified, the directory is recursively extracted. The owner, modification time, and access control list (including optional entries, unless the -A 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 -h option is specified.

-I path

The index on the current volume is extracted from the backup media and is written to path.

-V 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.

Magic Field

On valid fbackup media, it contains the value FBACKUP*LABEL (HP-UX 11i Version 3 and beyond). Previous values of this field were FBACKUP_LABEL (between HP-UX 10.20 and HP-UX 11i Version 2 inclusive) and FBACKUP LABEL (before HP-UX 10.20).

Machine Identification

This field contains the result of uname -m.

System Identification

This field contains the result of uname -s.

Release Identification

This field contains the result of uname -r.

Node Identification

This field contains the result of uname -n.

User Identification

This field contains the result of cuserid().

Record Size

This field contains the maximum length in bytes of a data record.


This field contains the time fbackup was started.

Media Use

This field contains the number of times the media has been used for backup.

Volume Number

This field contains a # character followed by 3 digits, and identifies the current volume in the backup.

Checkpoint Frequency

This field contains the number of data records between checkpoints.

Fast Search Mark Frequency

This field contains the number of files between fast search marks for backups made with DDS tape drives.

Index Size

This field contains the size of the index.

Backup Identification Tag

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.

-R path

An interrupted full recovery can be continued using this option. frecover uses the information in file path to continue the recovery from where it was interrupted. The only command line option used by frecover with this option is -f. The values in path override all other options to frecover. Note also that only full recoveries 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 -x option) is interrupted then restarted with this option, frecover 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:

-c config

config specifies the name of a configuration file to be used to alter the behavior of frecover. 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 (-S 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 specified action. Valid action identifiers are error, chgvol, and sync. Separators can be either tabs or spaces. In the following sample configuration file, each time an error is encountered, the script /var/adm/fbackupfiles/frecovererror is executed. The script /var/adm/fbackupfiles/frecoverchgvol is executed each time the backup media is to be changed. The maximum number of resynchronization attempts is five.

error /var/adm/fbackupfiles/frecovererror chgvol /var/adm/fbackupfiles/frecoverchgvol sync 5

-e path

path is interpreted as a graph to be excluded from the recovery. There is no limit on how many times the -e option can be specified.

-f device

device identifies the backup device to be used instead of the default /dev/rmt/0m or /dev/rtape/tape1_BEST on systems where legacy Device Special Files (DSF) is disabled. If device is -, frecover reads from standard input. Thus fbackup and frecover can be used in a pipeline to backup and recover a file system as follows:

fbackup -i /usr -f - | (cd /mnt; frecover -Xrf -)

If more than one output file is specified, frecover uses each one successively and then repeats in a cyclical pattern. Patterns can be used in the device name in a way similar to file name expansion as done by sh. 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 machine:device. frecover creates a server process, /usr/sbin/rmt, on the remote machine to access the tape device. If /usr/sbin/rmt does not exist on the remote system, frecover creates a server process from /etc/rmt 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 fast search marks capability is not used when accessing remote DDS devices.

-g graph

graph defines a graph file. Graph files are text files and contain the list of file names (graphs) to be recovered or skipped. Files are recovered using the -i option; so, for example, if the user wants to recover all of /usr, the graph file contains one entry:

i /usr

It is also possible to skip files by using the -e option. For example, if a user wants to recover all of /usr except for the subgraph /usr/lib, the graph file contains two entries:

i /usr e /usr/lib

If the graph file is missing, frecover 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.

-i path

path is interpreted as a graph to be included in the recovery. There is no limit on how many times the -i option can be specified.


Print a message each time a file marker is encountered. Using this option, frecover prints a message each time either a DDS fast search mark, 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 progressing during long, and otherwise silent, periods during the recovery.


Recover the file from the backup media irrespective of age. Normally frecover 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 frecover works silently. Verbose option. Displays the file type and name of each file processed.


Automatically answer yes to any inquiries.


Do not recover any optional entries in access control lists (ACLs). Normally, all access control information, including optional ACL entries, is recovered. This option drops any optional entries and sets the permissions of the recovered 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 /usr/bin/vi, /usr/bin/sh, and /etc/passwd to a local directory without creating each of the graph structures.

-E extarg

Specifies the handling of any extent attributes backed up by fbackup. The -E 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 system's block size is incompatible with the extent attributes. If -E is not specified, extarg defaults to warn.


(no recovery) Prevent frecover 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 -N and -v options together). Note that the listing of files produced with the -N and -v 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.

-S skip

frecover 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 frecover recovers files to their absolute path name.


Environment Variables

LC_COLLATE determines the order in which frecover expects files to be stored on the backup device and the order in which file names are output by the -I option.

LC_MESSAGES determines the language in which messages are displayed.

If LC_COLLATE and LC_MESSAGES are not specified in the environment or are set to the empty string, the value of LANG is used as a default for each unspecified or empty variable. If LANG is not specified or is set to the empty string, a default of "C" (see lang(5)) is used instead of LANG. If any internationalization variable contains an invalid setting, frecover behaves as if all internationalization variables are set to "C". See environ(5).

International Code Set Support

Single- and multi-byte character code sets are supported.


The fbackup, frecover, and ftio 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 pax 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 example, if the directories did not change since the last full backup. If frecover 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 frecover 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 uname() was increased (from 8 to 256). To accommodate the larger size, a format change was necessary. A new magic number, FBACKUP*LABEL, 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 number associated with this release through HP-UX 11i Version 2 (inclusive) is FBACKUP_LABEL.

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, fbackup creates tapes with a magic number that is only recognized on releases which support the features and format being archived. This prevents fbackup tape archives from being restored on earlier HP-UX systems than are supported. frecover still reads all tape formats so that fbackup tape archives created on earlier HP-UX systems can be restored.

The fbackup index format now includes the file size in the first field; the previous format simply had the '#' character in that field. The implementation provides both forward and backward compatibility between the old and new index formats. However, the file sizes are used in conjunction with the checkpoints to increase selective recovery speed on DLT devices, so recovery of an fbackup 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 fbackup to do a partial recovery, frecover attempts to use the DDS fast-search capability to find files on the tape more quickly. In order to do this, however, frecover 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 fbackup and frecover 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 substantially 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 frecover if there is not enough virtual memory available. If this happens, the user might consider adjusting the maxdsiz parameter 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 (/etc/passwd) must be recovered before attempting to recover any desired ACLs.

Network special files are obsolete. Therefore, frecover 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 LANG or LC_COLLATE environment variable, frecover 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 misspelled, this may cause confusing messages, such as frecover asking for the previous volume, when volume one is mounted.


frecover does not support QIC-120 and QIC-150 formats on QIC devices. If frecover is attempted for these formats, frecover fails and the following message is displayed :

mt lu X:Read must be a multiple of 512 bytes in QIC 120 and QIC 150


frecover was developed by HP.



Default backup device.


Default backup device if legacy DSF is disabled.

Printable version
Privacy statement Using this site means you accept its terms Feedback to webmaster
© 1983-2007 Hewlett-Packard Development Company, L.P.