dump/tar/star/etc (was Re: Interesting speed benchmarks)

Brian Reichert wrote:

On Sat, Jan 27, 2007 at 09:43:52AM +1100, Peter Jeremy wrote:


... dump/restore is the only tool ... tar, cpio and pax also have ... restrictions.



I thought 'star' handled sparse files and all the extra magic? Not
that this is germaine to the topic at hand...


The full picture is a little complicated. No one tool gets everything exactly right:

For sparse file support:
* dump fully handles them.
* gnutar and star use some guesswork to archive them into "gnutar format" archives; neither can guarantee that the final block layout matches the original
* gnutar, star, and bsdtar can all restore sparse files from "gnutar format" archives

For ACLs and file flags:
* I'm not sure about dump; I believe it handles file flags but not ACLs
* star and bsdtar fully support both using "pax extended" tar archives
* gtar, cpio, and pax do not support them

For long filenames and large files:
* dump should fully support both up to the limits of the filesystem
* star, bsdtar, and gnutar all support large files (64-bit lengths) using extended tar archives
* star and gnutar support filenames up to 1k (longest name supported by kernel system calls)
* bsdtar supports filenames up to 1meg, though with some limits (restoring dirs with names over 1k gets the permissions wrong sometimes)
* cpio and pax are more limited

I eventually want to replace cpio and pax with versions built on top of
libarchive (as bsdtar is), which will alleviate some of these issues.
(Though some are particular to the archive formats; there is no standard
cpio extension for long filenames or large files.)

Tim Kientzle

_______________________________________________
freebsd-current@xxxxxxxxxxx mailing list
http://lists.freebsd.org/mailman/listinfo/freebsd-current
To unsubscribe, send any mail to "freebsd-current-unsubscribe@xxxxxxxxxxx"

Relevant Pages

  • NEW TAR
    ... accepts the most popular gtar command-line options, ... bsdtar is not a clone of gtar. ... gtar can read ustar archives with no problem. ... for managing tape drives, including rmt support. ...
    (freebsd-current)
  • irritably crush this post-war attack
    ... If the broken creatures can support almost, ... habitat may need more archives. ...
    (sci.crypt)
  • Re: Aint it Pitiful Rogers and Kali cite a PUNK!!??
    ... You claimed to have the support of major researchers. ... You claimed to have a doctorate in psychology. ... that you were doing the posting to spp under the name of B.R.A.D. ... Archives show you have been foul-mouthed and sexist with ...
    (sci.psychology.psychotherapy)
  • RE: FBA rant
    ... attach the 3310/3370's directly to the processor without having to have ... we usually got excellent support for all geometries. ... send email to listserv@xxxxxxxxxxx with the message: GET IBM-MAIN INFO ... Search the archives at http://bama.ua.edu/archives/ibm-main.html ...
    (bit.listserv.ibm-main)
  • Re: [Full-Disclosure] Multiple AV Vendors ignoringtar.gz archives (fwd)
    ... here is a summary of a discussion with Mark at Eset for NOD32 about ... Subject: [support] Re: Multiple AV Vendors ignoringtar.gz archives ...
    (Full-Disclosure)