"Richard L. Hamilton" <[EMAIL PROTECTED]> wrote:
> I would think there's also a performance problem with backing up
> via network shares, at least compared to something that
> reads locally and streams the data to a backup server (where there would
> also have to be a way to read the data back from the backup server and
> stream it to a local restore program, as well as an index of the
> streamed data stored somewhere, to make finding specific files
> with particular attributes (modification time, size, etc) feasible.
>
> I suppose there must be a Windows equivalent of {tar, pax, cpio, ...},
> that is, a format that alternates headers describing pathnames and
> associated attributes with the accompanying file contents. But I'm not
> into Windows, so I don't know what that would be or what tools make
> it easy to use.
star runs on windows if you like, you may also use the cpio or pax
CLI form star.
star compiles using Cygwin and SFU, I have to admit that I still need to
check David Korn's UWIN.
Star implements a OS/FS independent true incremental backup.
> Personally, I think the ideal streaming format needs one other thing: a
> validity trailer for each file's data, that indicates at least either:
> * valid as described in the header
> or one or more of
> * file size changed to x bytes (could be higher or lower),
> data was read without I/O errors
> * file modification time changed upon 2nd check, data may be
> inconsistent
> * I/O error encountered at offset y, data up to that point is valid, after
> that is implementation dependent whether it's fill (preserve start of file
> data + header file size=trailer offset relationship) or best effort. I
> haven't seen
This is something I was planning for several years with star ;-)
Any tar needs to stay with the announced size.... star currently already
marks files with _extraction_ problems by setting the mtime to 0 (Jan 1st 1970).
Cpio (the format) supports crc for the files but it is expensive as you need
to read the file twice in order to put the checksum into the header.
Star could add trailer records for files that include a CRC, MD5, or whatever
and a hint on whether there was a I/O error or size change when creating the
archive.
Jörg
--
EMail:[EMAIL PROTECTED] (home) Jörg Schilling D-13353 Berlin
[EMAIL PROTECTED] (uni)
[EMAIL PROTECTED] (work) Blog: http://schily.blogspot.com/
URL: http://cdrecord.berlios.de/old/private/ ftp://ftp.berlios.de/pub/schily
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