More save sets on a magnetic tape

[geir_2]

Hi,
Is it possible to have more than one saveset on a tape?

If answer is yes, how do I access the save sets?

geir

[Uwe Zessin · Accepted solution]

Sure, just address them by their filename.

$ backup/list tape:SAV1.BCK
$ backup/list tape:SAV2.BCK
$ backup /rewind /list tape:SAV1.BCK

[Karl Rohwedder]

To find which savesets are on a tape, try
$ MOUNT/OVER=ID tape
$ DIR tape:

regards Kalle

[Uwe Zessin]

Right, except if your default context is on a logical name search list (like SYS$MANAGER) in which case you better use:

$ directory tape:[]

else, you will see 'duplicate' files, because some component picks up a dummy directory specification from the search list. Or has this changed in recent VMS versions?

[Steven Schweda]

To put more than one save set onto a tape, use
/REWIND on only the first BACKUP command when
writing the tape.

Also, you don't really _need_ to know the save
set names when reading the tape. Again, if
you use /REWIND on only the first BACKUP
command when reading the tape, each BACKUP
command will read the next save set. For
example:

BACKUP /NOASSIST /LIST tape_device: /REWIND
BACKUP /NOASSIST /LIST tape_device:
BACKUP /NOASSIST /LIST tape_device:
[...]

[Volker Halle]

Geir,

if you want to put multiple savesets on one tape, consider to use UNIQUE names for each of those savesets. It makes accessing them so muss less troublesome...

Volker.

[geir_2]

Hi,

Thanks for great answers.

I thought I should make a full image backup on the first saveset on the tape. The next savesets on the same tape will be incremental backup. (few files only). The name of the saveset will be the date.bck, (17-oct-2005.bck). Hope it's legal to do it??


First Command(Week 1) :

$ backup/image/record/since="-7-" disk1: -
$_ mka600:17-oct-2005.bck

Next Command:

$ backup/created/since=backup/record disk1: -
$_ mka600:18-oct-2005.bck

Maybe I also should include the journal qualifier? I will test it on the lab.

Thanks!!
Geir

[Volker Halle]

Geier,

don't forget /REWIND for the first saveset on tape.

Use /MODIFIED instead of /CREATED on the incremental backups, otherwise you will only back up new files and miss the modified ones.

Whether it would be a good idea to put the full and incremental backups onto ONE tape could also be up for discussion (how about: don't put all your eggs in one basket).

Volker.

[Uwe Zessin]

> backup/image/record/since="-7-"

/IMAGE is supposed to save *all* files on the disk. It is interesting to note that the combination of /IMAGE and /SINCE does not give an error or warning on a system I tried.

[Daniel Fernandez Illan]

Uwe
You are rigth.
HELP BACKUP/IMAGE show this message:

In save and copy operations, you cannot use input file-selection qualifiers with the /IMAGE command qualifier because BACKUP saves or copies all files on the input disk volumes.

I think that in BACKUP/IMAGE/SINCE /SINCE qualifier is overrided, and error message doesnot appears.

Geir
Qualifiers /INIT and /REWIND are similars when /IMAGE qualifier is used and output device is a tape.
Saludos.
Daniel.

[Jan van den Ende]

Geir,

consider using (mainly for human clarity, but still) using explicit /REWIND (for the intended first) and /NOREWIND (for all subsequent savesets of a tape.

As an aside:
note that, if any saveset for whatever reason does NOT write its end-of-file, then the start position of the next saveset can not be determined, hence that next backup will generate an error. (and without that knowledge, LOTS of time can get lost looking for a reason!).

Success.

Proost.

Have one on me.

jpe

[Uwe Zessin]

Oops, I hope I did not cause too much confusion when I slipped /REWIND in there. It was only to show that TAPE is a sequential media and you have to get back to the begin if you want to access a file that has passed the heads (well, not really true on a multi-track media, but I think you get the idea ;-)

[geir_2]

hi,

If the same dlt tape is mounted in the tape drive during the week, I assumed it's not necessary to use /norewind, when I want to create new savesets on the tape. The actual command procedure will be restarted every day during the week.

Simular I assume that it not necessary to use rewind, if I want create backup in the beginning of the tape, when I mount a new tape in the tape drive. Correct??

Geir

[Volker Halle]

Geir,

/NOREWIND is the default, but I would still suggest to explicitly specify /REWIND or /NOREWIND on the BACKUP command line, just for clarity and documentation purposes.

Volker.

[Uwe Zessin]

If you want to keep the same media in the drive you need to use
"DISMOUNT /noUNLOAD" at the end of the job.


It's been some time I have played with BACKUP, but I have a dim memory that it automatically jumps after the last file on tape to append if you use a normal BACKUP statement, unless you use BACKUP/REWIND - caution! as this will re-initialize the media!!

[Lawrence Czlapinski]

geir:
1. You want an explicit
$BACKUP/REWIND when you want to overwrite the tape for your next full backup, otherwise you will append to the tape.
2. I also agree that it is not good policy to have the full backup and incrementals on the same tape. If you would have a full backup tape go bad and they can go bad at any usage, then you've lost the full backup plus all incrementals since then. For the same reason, I wouldn't want my incrementals all on the same tape.
Lawrence