I too, have read the manual, and talked to TSM folk, about RAW vs. filesystem
usage. I must say, that because of ease, I have always used raw LV's and
never had a problem, and get very good performance.
If you are talking about AIX, OS mirroring takes place at the LV level, so
it is a piece of cake to due OS mirroring, with very little guess work.
Set up your LV, and do a mklvcopy, sync and your done. I use TSM mirroring for
the DB and log, and OS mirroring for STG pools, all LV based. Again, never a
problem.
bob
I too, have read the manual, and talked to TSM folk, and I have never had
On Tue, Oct 07, 2003 at 12:30:06PM -0500, Roger Deschner wrote:
> Yes, I am too easy to satisfy. That's because after a weekend of
> dsmfmt-ing, I'm declaring the thing BROKEN worse than before. I take
> back those nice things I said last Friday.
>
> I'm not using raw LVs because I want to use OS mirroring on my disk
> storage pools. Also the ITSM Administrator's Guide goes to some length
> to convince you not to use Raw LVs, and I tend to believe the basic
> manual for any product when they come out and say something and are that
> sure of it.
>
> What bewilders me now about dsmfmt is two questions:
>
> 1) Why does the error message tell me how big to specify for some disks
> and not for others? The Logical Volumes are identical except for size.
> On a 72gb disk, if I overestimate, it says how big to use. On a 36gb
> disk, it's like before, where I get to guess, and then wait several
> hours to find out if I guessed right or not.
>
> 2) Why is it's calculated number so low? After dsmfmt was done, the Unix
> df command showed that filesystem only 94% full, with nearly 5gb showing
> free on df on a 72gb disk. That's a lot of waste! I'm not so sure this
> new feature is such a great idea if it is going to forbid me from
> getting my disk as full as possible. By the old method of trial and
> error and waiting for hours, I could usually get it well over 99% full,
> according to the Unix df command.
>
> Now I really want that option you suggest - use it all (I mean, really
> use it all) and tell me how much space I've got when I'm done. The
> current state of affairs in V5.1 is worse than just wasting a lot of my
> time; now it is wasting my disk space as well, and it is behaving
> inconsistently.
>
> A consistently-behaving, easy to use to allocate all of something,
> version of dsmfmt is VITAL to disaster recovery capabilities!
>
> Roger Deschner University of Illinois at Chicago rogerd AT uic DOT
> edu
>
>
> On Fri, 3 Oct 2003, Joel Fuhrman wrote:
>
> >You are to easy to satisfy. I would like an option which says to use it all
> >and tell me what was used. That way I only have to do the dsmfmt once.
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