Messages in this thread | | | From | "Robert de Bath" <> | Date | Sat, 4 Sep 1999 11:23:55 +0100 (BST) | Subject | Re: Amanda VFAT Incremental Backups Broken in linux-2.2.1[12] |
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On Sat, 4 Sep 1999, Khimenko Victor wrote:
> In <9e86d1b443edfd13@home-box.demon.co.uk> Robert de Bath (rd103983@home-box.demon.co.uk) wrote: > > DONT BACKUP VFAT INCREMENTALLY ------------------------------ > > > There is only one date on a file on a VFAT partition and as every command > > down to the DOS copy command preserves that date you cannot see what's > > been changed. > > This is WRONG. VFAT (but NOT plain old MS-DOS FAT !!!) has three times as it > should be: Modification time (this is old good MS-DOS "modification time"; > preserved by copy), Creation time (not preserved by copy) and "Last access > time" (date actual -- time is not stored; not preserved by copy). At least it > is on disk -- I'm not sure if Linux's VFAT driver supports them... > > > Hopefully the ctime is being set to now (or now-1); this is the > > _right_ thing to do. > > Why so ? Why not use existing three times ? Even if "Last access time" is not > time but date...
Oh hum, I'd forgotten that VFAT had those times, but it's still not sufficient.
For unix:
mtime: The time the file was last modified. atime: The time the file was last accessed. ctime: The last time _any_ change was made to the file or inode.
All times are to the second.
For VFAT mtime: The time the file was last modified (2 second resolution) atime: The time the file was last accessed (86400 second resolution) ctime: The time the file was _created_ (1ms resolution)
I suppose the unix ctime could be the max of these times. I don't think I'd trust it enough to backup incrementally even tho it'd pick up the commonest problem of a single mtime; unpacked zip files.
-- Rob. (Robert de Bath <http://poboxes.com/rdebath>) <rdebath @ poboxes.com> <http://www.cix.co.uk/~mayday>
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