I will retract my statements in regards to disk space. I neglected to set the 
dtacpr(*HIGH) when saving to save files - hence the compression didn't take 
place - with the change to the save the save files took 383,324,160 - nearly a 
full 1 G less than the virtual tape backup.

"How does performance of virtual tape compare to save file? How does size on 
disk compare?"

Performance can depend a bit on system and implementation. If you have 10 
libraries to save off you can run 10 jobs at the same time if you're saving to 
save files - verses it being pretty much sequential saving off those same 10 
libraries on a savlib command to a virtual tape - depending on disk 
configuration and what not arguably the save file approach would be faster.

Based on the test I documented in an earlier post, I don't believe the disk 
requirements are significantly different. 

"Virtual tape does not compress like a save file will, and if you are saving
multiple libraries to it you will need as much DASD as the size of the 
libraries you are saving."

I have 2 libraries I save off to two save files in a library with only those 2 
save files - size is 1,344,323,584. The exact same libraries saved off to 
virtual tape takes up 1,345,744,896 - making a difference of 141,312. Not a 
significant difference in the big picture - not even a 1% variance.

Virtual tape does not compress like a save file will, and if you are saving
multiple libraries to it you will need as much DASD as the size of the libraries
you are saving.

How does performance of virtual tape compare to save file? How does size on disk
compare?

I see the post on VRTSAV sounds like it might be a winner?

Virtual tape device does not support /qntc.  Also, don't attempt to do an option
21 save to it... I had to call IBM to fix the mess that left.

I got past the authority problem by granting full control to the user ID common
to both platforms. Then I ran into a really bizarre system error, then the phone
rang and my day job pulled me away and beat me up real bad. I'll try again tomorrow.

Well - when I try to use QNTC path for this it complains about not having the 
proper authority - so if anybody finds out that this is possible, please give 
me some tips...

Does the virtual tape allow SAVLIB directly to network-attached storage
accessible through QNTC?

That would be nice.

Ah - that's the advantage. You can save with *LEAVE, then save something else.
So you don't have to monkey around with one save file per SAVxxx command.

Since this is an image catalog, you can transfer the stream files to another
system. If I received a directory with these stream files, can I just create the
virtual tape, or do I need to know how it was defined on the save system?

Virtual tape does not take any more room on disk than does a SAVF. They are just
as SAVF. YOu just have to go through the extra steps to create them using an
IMGCLG and same for restore. 

This has been around since they started SAVF stuff. You can also use multiple
save commands to a virtual tape and append the data to the virtual tape like you
would a regular tape. 

For quick restores, you would create a CL file and execute it.

Thank you Wilson!

Ralph,

You need to create an image catalog then you must "mount" it with LODIMGCLGE.
The Backup and Recovery manual is the best source to do it.

Virtual Tapes are useful to minimize backup downtime in production systems, just
like Bob said.

Wilson

I looked at an IBM example then created a *VRT tape devd and tried to save a 
file to it. I get a 'device not ready' msg. What am I doing wrong? Thanks.

I'm hearing from others that the virtual tape thing is the way to go. Preferred
over savf for production-style backups.

You say you need lots of dasd but I think the idea behind it (unless you have 
lots of asps, etc.) is that you create said file and ftp it off onto something, 
etc. I read the other day about it, haven't used it, and if it is anything like 
the crap you have to go thru for the ptf's with the virtual dvd drive, I concur 
it would be a pita.

How portable is the virtual tape? Is it like an image catalog, needing setup on
the restore system before you can use it? (In which case save files are probably
still a better option, even for multiple libraries.)

I have done the virtual tape drive thing, but you need loooots of DASD for that
option!

anybody doing the virtual tape drive thingy?

Steve,  

Obvious (had done that). 
Thanks.

Create a Temporary Library. Save each library you need into a SAVF in that 
Temp Lib.  Then save the Temp Lib to its own SAVF.

The restore would be a two stage process as well, but it would work.

by what if you do the virtual tape drive situation that exists in v5r4 and up 
where you can save like you are saving to a tape drive but it goes onto a file 
and the big plus for it is that you can save multiple libraries into the it, 
where you can't with savf?

anyone use this feature?

See, I don't have as much of a problem with this as I did the large return 
value issue since IBM tells you that you can only save ONE library when saving 
to a save file.

Amusing! About an hour ago I tried to save two libraries to a savf and 
rediscovered the 'one-library' limitation.

This:
SAVLIB LIB(RPGTOOLS RPGWORLD CGILIB CLASSANOV RPGOPEN ISOCKETS) 
DEV(*SAVF) SAVF(QGPL/COZZI)

Is not allowed? WTF?

You mean I can't save multiple libraries to one save file? What year is this?