Re: Checking large numbers of files

From	Dimiter_Popoff <dp@tgi-sci.com>
Newsgroups	comp.arch.embedded
Subject	Re: Checking large numbers of files
Date	2016-10-28 05:38 +0300
Organization	TGI
Message-ID	<nuudmc$vtv$1@dont-email.me> (permalink)
References	<nutuoo$k2$1@dont-email.me> <5812842a$0$63774$c3e8da3$38634283@news.astraweb.com> <nuu3mu$fp2$1@dont-email.me> <nuu5d5$k76$1@dont-email.me> <nuuasq$ogi$1@dont-email.me>

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On 28.10.2016 г. 04:50, Don Y wrote:
> Hi Dimiter,
>
> [Still 35C!  Cripes!!]

Hi Don,
we switched from walking around in shorts to winter uniform and
house heating almost a month ago...

> First, timestamps on "containers" (e.g., things like "folders")
> don't mean anything.  If /foo/A and /foo/B are "being tracked"
> but other contents of /foo are not, then the timestamp of /foo
> can change even though NEITHER A nor B have been altered!

Well yes, the last modification date of a directory may be
impractical to be kept up to date. I made this optional (by changing
the directory file type) some 20+ years ago...

But the file "last modification date" is pretty stable, can't see
it change for no good reason. I often do copy with the option to
overwrite only files which are older than the source to be copied,
has not bitten me so far.

>
> Also, I access/mount the volumes from a variety of different hosts
> and "maintain" the files with a variety of different utilities.
> The clocks on all of these hosts aren't guaranteed to be synchronized.
> So, you can't infer chronology from the timestamps.

Hmmm, when copying a file its timestamp should normally be copied
as well so local clocks should not matter re file contents.

> And, the mechanisms that I use to move files around may not
> preserve original timestamps, accurately.
>
> E.g., I may move files onto a volume over FTP -- using a client
> that doesn't propagate the timestamp of the *original* file.

This is an issue as old as ftp is, yes... If you use GET with
ftp the file timestamp can come correctly across (MLST). Still
no standard way to propagate the correct timestamp when you "STOR".

> So, that instance of the file now has a different timestamp
> from the original FROM WHICH IT WAS COPIED.  Yet, I *know*
> they are identical, in contents.

Well yes, using ftp "put" does that indeed - but I can't think
of another cause so it is soft of avoidable.

>
> [Imagine a scenario where a volume is failing; you'd much rather know
> about a file that is NOT present on a "backup copy" than be reassured
> that the contents of all the OTHER files are intact; you KNOW you
> will lose data due to the missing file but MIGHT not lose anything
> from those other files if you've not yet wasted time checking them!]

Well searching the whole tree for a particular name would be painful
but still faster than copying it all. I personally tend to know which
file belongs where so locating it is easy - but this is not much help
if you look into an archive you are not familiar with.

Dimiter

Thread

Checking large numbers of files Don Y <blockedofcourse@foo.invalid> - 2016-10-27 15:23 -0700
  Re: Checking large numbers of files Clifford Heath <no.spam@please.net> - 2016-10-28 09:48 +1100
    Re: Checking large numbers of files Don Y <blockedofcourse@foo.invalid> - 2016-10-27 16:48 -0700
      Re: Checking large numbers of files Dimiter_Popoff <dp@tgi-sci.com> - 2016-10-28 03:17 +0300
        Re: Checking large numbers of files Don Y <blockedofcourse@foo.invalid> - 2016-10-27 18:50 -0700
          Re: Checking large numbers of files Dimiter_Popoff <dp@tgi-sci.com> - 2016-10-28 05:38 +0300
            Re: Checking large numbers of files Don Y <blockedofcourse@foo.invalid> - 2016-10-27 21:33 -0700
      Re: Checking large numbers of files Clifford Heath <no.spam@please.net> - 2016-10-28 11:40 +1100
        Re: Checking large numbers of files Don Y <blockedofcourse@foo.invalid> - 2016-10-27 18:52 -0700
  Re: Checking large numbers of files kalvin.news@gmail.com - 2016-10-28 03:50 -0700
    Re: Checking large numbers of files Don Y <blockedofcourse@foo.invalid> - 2016-10-28 10:49 -0700
      Re: Checking large numbers of files kalvin.news@gmail.com - 2016-10-29 05:17 -0700
        Re: Checking large numbers of files Don Y <blockedofcourse@foo.invalid> - 2016-10-29 13:15 -0700
          Re: Checking large numbers of files Clifford Heath <no.spam@please.net> - 2016-10-30 09:47 +1100
            Re: Checking large numbers of files Don Y <blockedofcourse@foo.invalid> - 2016-10-29 16:19 -0700
              Re: Checking large numbers of files Don Y <blockedofcourse@foo.invalid> - 2016-10-29 16:36 -0700
              Re: Checking large numbers of files Clifford Heath <no.spam@please.net> - 2016-10-30 12:00 +1100
                Re: Checking large numbers of files Dimiter_Popoff <dp@tgi-sci.com> - 2016-10-30 04:05 +0200
                Re: Checking large numbers of files Clifford Heath <no.spam@please.net> - 2016-10-30 14:06 +1100
                Re: Checking large numbers of files Dimiter_Popoff <dp@tgi-sci.com> - 2016-10-30 05:48 +0200
                Re: Checking large numbers of files Don Y <blockedofcourse@foo.invalid> - 2016-10-29 22:33 -0700
                Re: Checking large numbers of files Clifford Heath <no.spam@please.net> - 2016-10-30 17:00 +1100
                Re: Checking large numbers of files (long) Don Y <blockedofcourse@foo.invalid> - 2016-10-31 04:43 -0700
                Re: Checking large numbers of files (long) David Brown <david.brown@hesbynett.no> - 2016-10-31 14:20 +0100
                Re: Checking large numbers of files (long) Don Y <blockedofcourse@foo.invalid> - 2016-10-31 08:02 -0700
                Re: Checking large numbers of files (long) David Brown <david.brown@hesbynett.no> - 2016-11-01 09:47 +0100
                Re: Checking large numbers of files (long) Don Y <blockedofcourse@foo.invalid> - 2016-11-01 04:36 -0700
                Re: Checking large numbers of files (long) David Brown <david.brown@hesbynett.no> - 2016-11-01 14:29 +0100
                Re: Checking large numbers of files (long) David Brown <david.brown@hesbynett.no> - 2016-11-01 15:16 +0100
                Re: Checking large numbers of files (long) Don Y <blockedofcourse@foo.invalid> - 2016-11-02 11:42 -0700
                Re: Checking large numbers of files Don Y <blockedofcourse@foo.invalid> - 2016-10-29 22:15 -0700
                Re: Checking large numbers of files Don Y <blockedofcourse@foo.invalid> - 2016-10-29 21:50 -0700
                Re: Checking large numbers of files Clifford Heath <no.spam@please.net> - 2016-10-30 17:14 +1100
                Re: Checking large numbers of files (long) Don Y <blockedofcourse@foo.invalid> - 2016-10-31 03:36 -0700
                Re: Checking large numbers of files (long) Clifford Heath <no.spam@please.net> - 2016-11-01 09:20 +1100
                Re: Checking large numbers of files (long) Don Y <blockedofcourse@foo.invalid> - 2016-11-01 02:23 -0700
                Re: Checking large numbers of files Don Y <blockedofcourse@foo.invalid> - 2016-10-29 21:20 -0700
                Re: Checking large numbers of files Clifford Heath <no.spam@please.net> - 2016-10-30 17:25 +1100
          Re: Checking large numbers of files Robert Wessel <robertwessel2@yahoo.com> - 2016-10-30 00:14 -0500
            Re: Checking large numbers of files Don Y <blockedofcourse@foo.invalid> - 2016-10-29 23:02 -0700
          Re: Checking large numbers of files David Brown <david.brown@hesbynett.no> - 2016-10-31 12:19 +0100
            Re: Checking large numbers of files Don Y <blockedofcourse@foo.invalid> - 2016-10-31 07:00 -0700
  Re: Checking large numbers of files Ali <abdulrazaq@gmail.com> - 2016-10-30 15:45 -0700
    Re: Checking large numbers of files Don Y <blockedofcourse@foo.invalid> - 2016-10-31 03:45 -0700

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