NAME

ufsdump − incremental file system dump

SYNOPSIS

/usr/lib/fs/ufs/ufsdump [options] [arguments] files_to_dump

DESCRIPTION

ufsdump backs up all files specified by files_to_dump (normally a whole file system or files within a file system changed after a certain date) to magnetic tape, diskette, or disk file. 

options is a single string of one-letter ufsdump options. 

arguments may be multiple strings whose association with the options is determined by order. That is, the first argument goes with the first option that takes an argument; the second argument goes with the second option that takes an argument, and so on. 

files_to_dump is required and must be the last argument on the command line.  It specifies the files to dump. Usually it identifies a whole file system by its raw device name (for example, /dev/rdsk/c0t3d0s6).  Incremental dumps (levels 1 to 9) of files changed after a certain date only apply to a whole file system.  Alternatively, files_to_dump can identify individual files or directories, in which case the dump level is set to 0.  In all cases, the files must be contained in the same file system, and the file system must be local to the system where ufsdump is being run. 

If no options are given, the default is 9uf /dev/rmt/0 files_to_dump. 

With most devices ufsdump can automatically detect the end-of-media. Consequently, the d, s, and t options are not necessary for multi-volume dumps, unless ufsdump does not understand the way the device detects the end-of-media, or the files are to be restored on a system with an older version of the restore command. 

OPTIONS

0−9 The “dump level.” All files specified by files_to_dump that have been modified since the last ufsdump at a lower dump level are copied to the dump_file destination (normally a magnetic tape device).  For instance, if a “level 2” dump was done on Monday, followed by a “level 4” dump on Tuesday, a subsequent “level 3” dump on Wednesday would contain all files modified or added since the “level 2” (Monday) backup.  A “level 0” dump copies the entire file system to the dump_file. 

a archive_file
Archive file. Archive a dump table-of-contents in the specified archive_file to be used by ufsrestore(1M) to determine whether a file is in the dump file that is being restored. 

b factor
Blocking factor. Specify the blocking factor for tape writes. The default is 20 blocks per write for tapes of density less than 6250BPI (bytes-per-inch).  The default blocking factor for tapes of density 6250BPI and greater is 64.  The default blocking factor for cartridge tapes (c option) is 126.  The highest blocking factor available with most tape drives is 126.  Note: the blocking factor is specified in terms of 512-byte blocks, for compatibility with tar(1). 

c Cartridge.  Set the defaults for cartridge instead of the standard half-inch reel.  This sets the density to 1000BPI and the blocking factor to 126.  Since ufsdump can automatically detect the end-of-media, only the blocking parameter normally has an effect.  This option can also be used for 8mm tape. However, since the size (length) and density of 8mm tape differs from 1/4-inch cartridge, if ufsdump has difficulty detecting the end-of-media on a 8mm drive, these parameters should be specified (with the s and d options) directly.  This option is incompatible with the d option, unless you specify a density of 1000BPI with that option.  When cartridge tapes are used, and this option is not specified, ufsdump will slightly miscompute the size of the tape.  If the b, d, s or t options are specified with this option, their values will override the defaults set by this option. 

d bpi Tape density.  Not normally required, as ufsdump can detect end-of-media.  This parameter can be used to keep a running tab on the amount of tape used per reel.  The default density is 6250BPI except when the c option is used for cartridge tape, in which case it is assumed to be 1000BPI per track.  Typical values for tape devices are:

1/2" tape 6250 BPI

1/4" cartridge 1000 BPI

2.3-Gbyte 8mm tape 54,000 BPI

5.0-Gbyte 8mm tape 54,000 BPI

D Diskette.  Dump to diskette. 

f dump_file
Dump file. Use dump_file as the file to dump to, instead of /dev/rmt/0. If dump_file is specified as −, dump to standard output. 

If the name of the file is of the form machine:device, the dump is done from the specified machine over the network using rmt(1M).  Since ufsdump is normally run by root, the name of the local machine must appear in the /.rhosts file of the remote machine.  If the file is specified as user@machine:device, ufsdump will attempt to execute as the specified user on the remote machine.  The specified user must have a .rhosts file on the remote machine that allows the user invoking the command from the local machine to access the remote machine. 

l Autoload.  When the end-of-tape is reached before the dump is complete, take the drive offline and wait up to two minutes for the tape drive to be ready again. This gives autoloading (stackloader) tape drives a chance to load a new tape.  If the drive is ready within two minutes, continue. If it is not, prompt for another tape and wait. 

n Notify all operators in the operator group that ufsdump requires attention by sending messages to their terminals, in a manner similar to that used by the wall(1M) command.  Otherwise, such messages are sent only to the terminals (such as the console) on which the user running ufsdump is logged in. 

o Offline.  Take the drive offline when the dump is complete or the end-of-media is reached and rewind the tape, or eject the diskette. In the case of some autoloading 8mm drives, the tape is removed from the drive automatically.  This prevents another process which rushes in to use the drive, from inadvertently overwriting the media. 

s size Specify the size of the volume being dumped to.  Not normally required, as ufsdump can detect end-of-media.  When the specified size is reached, ufsdump waits for you to change the volume.  ufsdump interprets the specified size as the length in feet for tapes and cartridges, and as the number of 1024-byte blocks for diskettes. The values should be a little smaller than the actual physical size of the media (for example, 425 for a 450-foot cartridge).  Typical values for tape devices depend on the c option, for cartridge devices, and the D option for diskettes:

1/2" tape 2300 feet

60-Mbyte 1/4" cartridge 425 feet

150-Mbyte 1/4" cartridge 700 feet

2.3-Gbyte 8mm 6000 feet

5.0-Gbyte 8mm 13000 feet

diskette 1422 blocks (Corresponds to a 1.44-Mbyte diskette, with one cylinder reserved for bad block information.) 

S Size estimate.  Determine the amount of space that is needed to perform the dump without actually doing it, and display the estimated number of bytes it will take. This is useful with incremental dumps to determine how many volumes of media will be needed. 

t tracks
Specify the number of tracks for a cartridge tape. Not normally required, as ufsdump can detect end-of-media.  The default is 9 tracks.  The t option is not compatible with the D option.  Values for Sun-supported tape devices are:

60-Mbyte 1/4" cartridge 9 tracks

150-Mbyte 1/4" cartridge 18 tracks

u Update the dump record.  Add an entry to the file /etc/dumpdates, for each file system successfully dumped that includes the file system name, date, and dump level. 

v Verify.  After each tape or diskette is written, verify the contents of the media against the source file system. If any discrepancies occur, prompt for new media, then repeat the dump/verification process. The file system must be unmounted. 

w Warning. List the file systems that have not been backed up within a day.  This information is gleaned from the files /etc/dumpdates and /etc/vfstab.  When the w option is used, all other options are ignored.  After reporting, ufsdump exits immediately. 

W Warning with highlight. Similar to the w option, except that the W option includes all file systems that appear in /etc/dumpdates, along with information about their most recent dump dates and levels.  File systems that have not been backed up within a day are highlighted. 

EXAMPLES

To make a full dump of a root file system on c0t3d0, on a 150-MByte cartridge tape unit 0, use:

example# ufsdump 0cfu /dev/rmt/0 /dev/rdsk/c0t3d0s0

To make and verify an incremental dump at level 5 of the usr partition of c0t3d0, on a 1/2" reel tape unit 1, use:

example# ufsdump 5fuv /dev/rmt/1 /dev/rdsk/c0t3d0s6

To make a full backup of the entire disk c0t3d0, on an 8mm tape drive 2, use:

example# ufsdump 0fu /dev/rmt/0 /dev/rdsk/c0t3d0s2

FILES

/dev/rmt/0 default unit to dump to

/etc/dumpdates dump date record

/etc/group to find group operator

/etc/hosts to gain access to remote system with drive

/etc/vfstab list of file systems

SEE ALSO

cpio(1), tar(1), rmt(1M), shutdown(1M), ufsrestore(1M), wall(1M)

DIAGNOSTICS

While running, ufsdump emits many verbose messages. 

ufsdump exit codes:

0 Normal exit. 

1 Startup errors encountered. 

3 Abort − no checkpoint attempted. 

NOTES

Read Errors

Fewer than 32 read errors on the file system are ignored. 

Process Per Reel

Because each reel requires a new process, parent processes for reels that are already written hang around until the entire tape is written. 

Operator Intervention

ufsdump requires operator intervention on these conditions: end of volume, end of dump, volume write error, volume open error or disk read error (if there are more than a threshold of 32).  In addition to alerting all operators implied by the n option, ufsdump interacts with the operator on ufsdump’s control terminal at times when ufsdump can no longer proceed, or if something is grossly wrong.  All questions ufsdump poses must be answered by typing yes or no, as appropriate. 

Since backing up a disk can involve a lot of time and effort, ufsdump checkpoints at the start of each volume.  If writing that volume fails for some reason, ufsdump will, with operator permission, restart itself from the checkpoint after a defective volume has been replaced. 

Suggested Dump Schedule

It is vital to perform full, “level 0”, dumps at regular intervals.  When performing a full dump, bring the machine down to single-user mode using shutdown(1M).  While preparing for a full dump, it is a good idea to clean the tape drive and heads.  Incremental dumps should be performed with the system running in single-user mode. 

Incremental dumps allow for convenient backup and recovery of active files on a more frequent basis, with a minimum of media and time.  However, there are some tradeoffs.  First, the interval between backups should be kept to a minimum (once a day at least).  To guard against data loss as a result of a media failure (a rare, but possible occurrence), capture active files on (at least) two sets of dump volumes.  Another consideration is the desire to keep unnecessary duplication of files to a minimum to save both operator time and media storage.  A third consideration is the ease with which a particular backed-up version of a file can be located and restored.  The following four-week schedule offers a reasonable tradeoff between these goals. 

Sun MonTueWedThuFri
Week 1:Full55553
Week 2:55553
Week 3:55553
Week 4:55553

Although the Tuesday through Friday incrementals contain “extra copies” of files from Monday, this scheme assures that any file modified during the week can be recovered from the previous day’s incremental dump. 

Process Priority of ufsdump

ufsdump uses multiple processes to allow it to read from the disk and write to the media concurrently.  Due to the way it synchronizes between these processes, any attempt to run dump with a nice (process priority) of ‘−5’ or better will likely make ufsdump run slower instead of faster. 

BUGS

The /etc/vfstab file does not allow the desired frequency of backup for file systems to be specified (as /etc/fstab did).  Consequently, the w and W options assume file systems should be backed up daily, which limits the usefulness of these options. 
 
 

Sun Microsystems  —  Last change: 13 Feb 1992