Star saves many files together into a single tape or disk archive, and can restore individual files from the archive.
It includes a FIFO for speed, a pattern matcher, multivolume support, the ability to archive sparse files, automatic archive format detection, automatic byte order recognition, automatic archive compression/decompression, remote archives and special features that allow star to be used for full backups.
S tar also includes `rmt', a truly portable version of the remote tape server that supports remote operation between different OS and machine architectures (hides even Linux oddities) and a portable `mt' tape drive control program that is able t
The RMT program if 100% compatible with Sun's extensions for inter-platform operability support (MT status codes) and with GNU extensions for inter-platform open() nteroperability. In addition, it includes my enhancements that hide Linux MT-ioctl non compliances with other UNIX platforms.
Star is the fastest known implementation of a tar archiver. Star is even faster than ufsdump in nearly all cases.
Star development started 1982, the first complete implementation has been done in 1985. I never did my backups with other tools than star.
Here are some key features of "S tar":
- fifo
keeps the tape streaming. This gives you faster backups than you can achieve with ufsdump, if the size of the filesystem is > 1 GByte.
- remote tape support
a fast RMT implementation that has no probems to saturate a 100 Mb/s network.
- accurate sparse files
star is able to reproduce holes in sparse files accurately if the OS includes the needed support functions. This is currently true for Solaris-2.3 to Solaris-2.5.1
- pattern matcher
for a convenient user interface (see manual page for more details). To archive/extract a subset of files.
- sophisticated diff
user tailorable interface for comparing tar archives against file trees. This is one of the most interesting parts of the star implementation.
- no namelen limitation
Pathnames up to 1024 Bytes may be archived. (The same limitation applies to linknames)
This limit may be expanded in future without changing the method to record long names.
- deals with all 3 times
stores/restores all 3 times of a file (even creation time)
With POSIX.1-2001 the times are in nanosecond granularity.
Star may reset access time after doing backup. On Solaris this can be done without changing the ctime.
- does not clobber files
more recent copies on disk will not be clobbered from tape
This may be the main advantage over other tar implementations. This allows automatically repairing of corruptions after a crash & fsck (Check for differences after doing this with the diff option).
- automatic byte swap
star automatically detects swapped archives and transparently reads them the right way
- automatic format detect
star automatically detects several common archive formats and adopts to them. Supported archive types are: Old tar, gnu tar, ansi tar, star, POSIX.1-2001 PAX, Sun's Solaris tar.
- automatic compression detect
star automatically detects whether the archive is compressed. If it has been compressed
with a compression program that is compatible to decompression with "gzip" or "bzip2", star automatically activates decompression.
- fully ansi compatible
Star is fully ANSI/Posix 1003.1 compatible. See README.otherbugs for a complete description of bugs found in other tar implementations. Star is the first tar implementation that supports POSIX.1-2001.
- support for ACLs and file flags
star supports Access Control Lists and extened file flags (as found on FreeBSD and Linux). Support to archive and restore other file properties may easily added.
- support for all inode metadata
star supports to put all inode metadata on the archive. This allows star to perform true incremental dumps.
- sophisticated error control
allows to tell star which error types should be ignored for wich file name pattern.
This allows to write backup scripts that give no error messages for all problems that are tolerable (e.g. growing log files).
- 'ed' like pattern substitutuions
star supports automated pattern rule based file name substitution as documented for 'pax'.
- fast built in -copy mode
allows to make fast and accurate copies and directory tree comparisons.
star supports automated pattern rule based file name substitution as documented for 'pax'.
- True incremental dump/restore features
star is the first TAR based backup system that has been verified to handle typical file system changes correctly.
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