[Info-vax] SSSU command ?

[Forster, Michael]

As I previously posed and guessed though he hasn't responded, he's trying or responsible to manage a Cache environment he's not familiar with. Perhaps he's the unwilling or unwitting support?

Michael
________________________________________
From: Info-vax [info-vax-bounces at rbnsn.com] on behalf of Stephen Hoffman [seaohveh at hoffmanlabs.invalid]
Sent: Tuesday, October 23, 2012 5:52 PM
To: info-vax at rbnsn.com
Subject: Re: [Info-vax] SSSU command ?

On 2012-10-23 21:43:38 +0000, Steven Schweda said:

>    Although you provided no description of your environment,
> the path names suggest some kind of Windows system.  Why are
> you asking what looks like a Windows question in a VMS forum?
>
>    You might get better answers sooner in some appropriate
> forum.  Moreover, including some clues as to your OS (and its
> version) and other such info can be more helpful than
> expecting your readers to read your mind as well as your
> posting.

SSSU is the StorageWorks Storage System Scripting Utility
<http://h10032.www1.hp.com/ctg/Manual/c00674636.pdf> for Command View
EVA, using Cross Vraid Snapclones or Cross Vraid Snapshot capabilities.
 (That may not be the most current version of that SSSU document.)

I don't trust block- and controller-level backup tools to provide a
consistent copy of a running disk.  In my experience, the I/O
controllers don't and inherently can't know enough about the I/O
context and host caching and host transactions to be able to determine
if the disks are in a consistent state, after all.  The first time I
saw this problem was back in the 1980s with the faux shared-write
clustering products that were briefly available prior to VAX/VMS V4.0.
I've seen various subsequent attempts, too.

You might get lucky and split off the volumes at the "right" moment, or
you might get part of a multi-part I/O transaction and not the rest.

Are you feeling lucky?

And yes, you can potentially improve your luck by figuring out how to
quiesce your application I/O traffic prior to the split, or by using a
database and its transactional capabilities.

I'd love to be wrong here, too.  Getting the host involved is always a
mess, and some applications can tend to be uncooperative.

But I digress...

To the OP: it is probably best to call HP Support, and ask for their
recommendation here.  With the pile of hardware and software gear you
have here, you're paying for that support, so you might as well use it.


--
Pure Personal Opinion | HoffmanLabs LLC

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