Very Computer

I'm not sure that 'makesysb' is the best thing to use for backing up user
files.

As of 3.2, makesysb now uses 'tar'.  Unless IBM has done something to tar, it has a hard limit of 128 characters for file paths.  Can you guarrantee that none of your users will create files with paths longer than 128 characters?

Also, at least with a net install, the installation process does not preserve the timestamps on the files (all files get their timestamps set to the date/time of the restore).  I don't even like this for system files!

It's probably best to use makesysb to make bootable backups of /, /usr, /var,
and /tmp and use 'backup' (or something better) to backup user files.

Does anyone have experience with BRU or BUD on RS6000's?

-Rick

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|E20 Clark Hall, Ithaca, N.Y. 14853          cornell!msc.cornell.edu!rick|

Quote:> you said:
> As of 3.2, makesysb now uses 'tar'.  Unless IBM has done something to tar,
> it has a hard limit of 128 characters for file paths.  Can you guarrantee
> that none of your users will create files with paths longer than 128
> characters?

> but man tar:

> If you use a relative path
>   when specifying the File parameter, the path name must not be
>   more the 256 characters, and file names within the path name must
>   not be longer than 100 characters and must not contain blanks.

> hmmm is this different for 3.2?
> we're running 2006 (3.1.6) and we believe backups should be referenced
> from . not / (so you can restore anywhere.
> am i missing something???

> bill pociengel

'man tar' on Convex or Sun does not specify pathname limits.  If you create
a deeply nested directory (140 characters) on an RS6000, tar it, and restore it,
it works.  This is nice.

If you try to restore the same tar file on a Sun or a Convex, you
get only the directories up to a pathname length of 128 characters.  No error
message.  This is not nice.

I think we are all missing something.

-Rick

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|E20 Clark Hall, Ithaca, N.Y. 14853          cornell!msc.cornell.edu!rick|

  Yow!  It looks as though IBM _has_ done something to tar!  (By this I mean
  'differently from other vendors' rather than 'differently from AIX 3.1 to
  AIX 3.2'.)

The "normal" limit on names in tar is 100 characters.  If you create a leaf
name longer than this, even on aix, you get an error message.

But if you have a path name longer than 100, aix tar uses some of the
"extra" space (same place where the symbolic user and group names are
stored) to store the elements of the path name up to the leaf, and stores
just the leaf name in the normal name space.  So if you restore this file on
some other system, you get the file back, but somewhere farther up the
hierarchy than it was when you stored it.

  If you try to restore the same tar file on a Sun or a Convex, you
  get only the directories up to a pathname length of 128 characters.  No error
  message.  This is not nice.

I think you'll find it's 100, not 128.  You won't get an error message
because there is nothing wrong with the tar file.  If there is a bug here,
it's that aix tar didn't warn you that it was storing the file in a
non-standard way, and that other versions of tar wouldn't be able to restore
it correctly.

I never use single user mode to do any backups.  Since backup or tar backup
work on a file basis , and do not backup the filesystem as an image, there
is no need to worry about capturing the filesystem in an inconsistent state.
Besides, if you backing up mostly readonly stuff (its effectively all read-only
in my case since I exclude /home from my mksysb backups) there isnt even
a file consistency problem.
--
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