Re: Backup /ALIAS question
From: AEF (spamsink2001_at_yahoo.com)
Date: 03/01/05
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Date: 1 Mar 2005 08:22:41 -0800
Syltrem wrote:
> "AEF" <spamsink2001@yahoo.com> a écrit dans le message de
> news:1109648336.332378.165940@f14g2000cwb.googlegroups.com...
> >
> > Syltrem wrote:
> > > I use /NOALIAS whenever I do a /IMAGE
> > >
> > > But the problem is on the restore operation.
> > > When restoring directories with aliases, I have to manually do
SET
> > > FILE/ENTER after the restore.
> > >
> > > $ back sys$sysdevice:[sys*...]*.*.*/noalias
> > > $1$dga64:[temp]s.bck/sav/igno=int
> > > erl
> > > %BACKUP-W-ADNOTSAVED, alias directory
> > SYS$SYSDEVICE:[SYS0]SYSCOMMON.DIR;1
> > > and it
> > > s directory tree not saved
> > > %BACKUP-W-ADNOTSAVED, alias directory
> > SYS$SYSDEVICE:[SYS1]SYSCOMMON.DIR;1
> > > and it
> > > s directory tree not saved
> > > %BACKUP-W-AFNOTSAVED, alias file
SYS$SYSDEVICE:[SYS0]SYSCOMMON.DIR;1
> > was not
> > > sav
> > > ed
> > > %BACKUP-W-AFNOTSAVED, alias file
SYS$SYSDEVICE:[SYS1]SYSCOMMON.DIR;1
> > was not
> > > sav
> > > ed
> > > $
> > > $ back $1$dga64:[temp]s.bck/sav $1$dga64:[temp...]*.*.*/alias
> > > $ dir $1$dga64:[temp.sys0]SYSCOMMON.dir
> > > %DIRECT-W-NOFILES, no files found
> > >
> > > This is very cumbersome.
> > >
> > > If, otoh, I use the /ALIAS qualifier in the backup, the restore
will
> > create
> > > multiple copies of the files, which is somewhat worse.
> > >
> > > Anyone knows how to do a good restore with file aliases? I can
> > recreate them
> > > manually because I know what they are on my system, but it's far
from
> > being
> > > ideal.
> >
> > Why would you want to do this? If you are restoring a system disk,
you
> > need to use /IMAGE and then the aliases are restored properly. The
> > BACKUP utility was not designed with what you want to do here in
mind.
> >
> > IOW: Why would you want [temp.sys0...], [temp.sys1...], etc., with
all
> > the "common directories" aliased as they would be on a regular
system
> > disk?
>
> This was just an example.
> Usually I do this to restore to the original directory in its
original
> location (albeit on a different disk) of course
> But the end result is the same
>
> I believe David and John are right that there is a difference in the
way
> directory files (.DIR) are backed up/restored with the /IMAGE
qualifier.
They are correct. The restoration of .DIR files is very different. In
/IMAGE restores, the .DIR files are restored "as is". In non-image
restores the .DIR files are created only if they don't exist. It is as
if you were creating the entire directory path for each file.
So if you are restoring a non-image save set that contains
[AAA]BBB.DIR
[AAA.BBB]FILE.TXT
[AAA.BBB]FILE2.TXT
then the following happens:
BBB.DIR is created empty if it does not already exist. If it does
already exist, then nothing is done. FILE.TXT is added to [AAA.BBB] and
given a new FID on the fly. FILE2.TXT is added to [AAA.BBB] and given a
new FID on the fly. Since data from the .DIR file is not copied to the
disk, any aliases are lost.
(If /INCREMENTAL is specified, then the .DIR files are updated as
needed for incremental restorations. For example, directory entries
must be created for files that existed at the save-time of the current
save set, but were saved to a previous save set. This would mean that
the data in the .DIR files is saved even in non-image save sets
(perhaps sans FID's).)
>
> Thing is, for instance, that I recently wanted to move my Multinet
> installation to a test machine. Didn't want the entire disk, just
> [MULTINET...] so I could not use /IMAGE. And I had to manually
recreate the
> aliases after the restore.
That is correct. BACKUP is not designed to do that as I said in my
previous post.
> Normally you want to do this for a system disk, and you do use
> /IMAGE/NOALIAS, and I believe it would work.
> Let's see:
> $ mount dka100: /for
> $ back/image/noalias dka0: dka100:
> $ mount dka100 /over=id popo popo
> $ dir/fil dka100:[sys%]syscommon.dir
>
> Directory DKA100:[SYS0]
> SYSCOMMON.DIR;1 (12,1,0)
> Total of 1 file.
> Directory DKA100:[SYSE]
> SYSCOMMON.DIR;1 (12,1,0)
> Total of 1 file.
>
> Grand total of 2 directories, 2 files.
>
> With /IMAGE all is fine.
>
> So it appears we have to keep track of aliases if not using the
/IMAGE
> qualifier (as per first example above). Not good.
Correct. Only /IMAGE will preserve aliases. (Would /INCREMENTAL restore
any new aliases? I'll have to try that one day.)
It seems to me that aliases in VMS were made primarly (and perhaps
only) to support the SYSCOMMON structure and BACKUP/IMAGE was designed
to handle it properly. For other (non-documented) uses you are
basically on your own.
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