Re: LTO4 storage

[Roberto José Etcheverry Romero <yggdrasil.raiker@xxxxxxxxx>]

I just found out that the hard way. I was restoring the v5r3 machine that
got it's cable unplugged while rebuilding the LoadSource. And lo and behold
i faced an "Critical storage condition". I had changed a 5074 exp with lots
of small disk for a 0595 with 12 36G disks. I was just 20Gb under the
original ASP size. They used LTO2 for backup (and a 2849 controller,
SLOOOOOW) so imagine my surprise when a 200Gb tape (200/400) fills a 474Gb
ASP...
Original ASP was 500Gb and was 93% occupied. I thought they must have lots
of spoolfiles or the like for an  op21 to occupy only a 200Gb tape, but it
seems DB2 data is highly compressible.

Best Regards!


On Mon, Jun 10, 2013 at 9:50 AM, <rob@xxxxxxxxx> wrote:

> These numbers are in MB.  So the one fit 3TB on one LTO4 and had room to
> spare while the other only had 0.7TB and went to a second tape.
>
> Rob Berendt
> --
> IBM Certified System Administrator - IBM i 6.1
> Group Dekko
> Dept 1600
> Mail to:  2505 Dekko Drive
>           Garrett, IN 46738
> Ship to:  Dock 108
>           6928N 400E
>           Kendallville, IN 46755
> http://www.dekko.com
>
>
>
>
>
> From:   rob@xxxxxxxxx
> To:     midrange-l@xxxxxxxxxxxx,
> Date:   06/10/2013 08:31 AM
> Subject:        LTO4 storage
> Sent by:        midrange-l-bounces@xxxxxxxxxxxx
>
>
>
> I am noticing that DB2 or 'traditional' stuff really compresses when
> saving to tape but stream file stuff doesn't.
> I have one system that is primarily 'traditional' stuff and PRTERRLOG
> TYPE(*VOLSTAT) VOLTYPE(3590) after a full system save says it fit
> 3,087,925 on one LTO4 tape and that got everything.
> I have another system that's primarily stream file stuff and it only fit
> 1,024,936 on one tape and 689,570 on the second.
> Full system saves, identical control groups.  Saved with BRMS.
> Perhaps stream file are generally more compressed while DB2 stuff keeps
> all that non variable length data all filled with blanks and stuff.
>
>
> Rob Berendt
> --
> IBM Certified System Administrator - IBM i 6.1
> Group Dekko
> Dept 1600
> Mail to:  2505 Dekko Drive
>           Garrett, IN 46738
> Ship to:  Dock 108
>           6928N 400E
>           Kendallville, IN 46755
> http://www.dekko.com
>
> --
> This is the Midrange Systems Technical Discussion (MIDRANGE-L) mailing
> list
> To post a message email: MIDRANGE-L@xxxxxxxxxxxx
> To subscribe, unsubscribe, or change list options,
> visit: http://lists.midrange.com/mailman/listinfo/midrange-l
> or email: MIDRANGE-L-request@xxxxxxxxxxxx
> Before posting, please take a moment to review the archives
> at http://archive.midrange.com/midrange-l.
>
>
> --
> This is the Midrange Systems Technical Discussion (MIDRANGE-L) mailing list
> To post a message email: MIDRANGE-L@xxxxxxxxxxxx
> To subscribe, unsubscribe, or change list options,
> visit: http://lists.midrange.com/mailman/listinfo/midrange-l
> or email: MIDRANGE-L-request@xxxxxxxxxxxx
> Before posting, please take a moment to review the archives
> at http://archive.midrange.com/midrange-l.