Re: Predicting when we'll need an extra tape. -- MIDRANGE-L

If you are compressing, there's no way to predict exactly what the resulting size will be without running through the compression first - Catch-22! But if you have enough history, you might be able to use some heuristic process to learn from the past. It'd still be a guess along the lines of predicting the stock market, I think.

At 11:15 AM 5/16/2005, you wrote:

We like to use the results of the PRTERRLOG TYPE(*VOLSTAT) to predict when
we'll need another tape cartridge in our drive to perform the backup.
However, it seems that some items can apparently write much more data to
the cartridge.  I suspect that it depends on the compressibility of the
data.  I combined all the output from our various boxes to one report:

Volume          ---Temporary Errors---   --------M Bytes--------
ID                    Read       Write         Read      Written
SFRI11                   0           0            1       336537
GFRI11                   0           0            1        22664
WFRI11                   0           0            1        18984
DFRI11                   0           0            1       283125
DFRI21                   0           0            1       155981
HFRI11                   0           0            1       220831
6FRI1                    0           0            1       223611
6FRI2                    0           0            1       223913
6FRI3                    0           0            1       223380
6FRI4                    0           0            1       210898
01WK2                    0           0            1       117170
02WK2                    0           0            1       110359
03WK2                    0           0            1       105878
04WK2                    0           0            1       112585
05WK2                    0           0            1       114559
06WK2                    0           0            1        65112

All backups except for the ??WK2 set were done to 3582 LTO2 tape drives.
The ??WK2 was done to a 3581 LTO1 tape drive.

The S* backup was from a combination of libraries and IFS objects on our
development partition on the 520.
The G* backup was from a combination of libraries and IFS objects on a
little test 270 that's hardly ever used.
The W* backup was from a combination of libraries and IFS objects on a
partition on our 570 that is mostly Domino.
The D* backup was from Domino IFS objects on our busy partition on our
570.
The H* backup was all of our BPCS, payroll, and some IFS objects other
than Domino on our busy partition on our 570.
The 6FRI* backup was a SAVOBJ of some huge highly compressed objects in a
library created by the old ADSM (being phased out by TSM on this machine)

Problem statement:
How can I tell when the S* backup will need another tape cartridge?


6FRI* backup SAVOBJ does the following:
Library     Object                            SIZE   Object    Object
                                                     Type      Attribute
PCBACKUP    PCBACKUP00             262,209,286,144   *FILE     PF
PCBACKUP    PCBACKUP01             262,209,286,144   *FILE     PF
PCBACKUP    PCBACKUP06             104,884,985,856   *FILE     PF
PCBACKUP    PCBACKUP07              52,445,650,944   *FILE     PF
PCBACKUP    PCBACKUP11              52,445,650,944   *FILE     PF
PCBACKUP    PCBACKUP12              52,445,650,944   *FILE     PF
PCBACKUP    PCBACKUP02              52,443,553,792   *FILE     PF
PCBACKUP    PCBACKUP03              52,443,553,792   *FILE     PF
...

Rob Berendt
--
Group Dekko Services, LLC
Dept 01.073
PO Box 2000
Dock 108
6928N 400E
Kendallville, IN 46755
http://www.dekko.com

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