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From: Stan Sieler[SMTP:[log in to unmask]]
Sent: Friday, November 01, 1996 9:17 AM
To: [log in to unmask]
Subject: Re: HP3000 Data Cntr Mgmt Survey
>Hi all,
>I was filling out my responses to the survey, and noticed that on a large
>number of them my response was:
<Good information snipped>
>> Immediate switching of volume sets to 2nd |
>> system in case of system failure |_________ |_________
>
> This needs a better description, as I can see 3 explanations for
> it:
>
> 1) allow the disks of MPEXL_SYSTEM_VOLUME_SET (let's call it SYS)
> to be moved from one computer and then connected (presumably by
> uncabling & recabling) to a new computer, as a new & separate
> volume set (not SYS)
>
> This would have repercussions on the design of volume sets,
> particularly the group/account directory stuff.
> However, it might lead to much needed rethinking of that aspect
> of volume sets.
>
> 2) allow the disks of some volume set (other than SYS) to be
> moved (ditto) to another computer. Note that this would require
> either work in volume set design, or that the second computer
> already have the group/accounts setup.
>
> Been there, done that. This is already feasible today, with
> no extra hardware, no extra software.
>
> 3) Design/build/sell a fancy hardware switch that allows
> specific individual disk drives on a SCSI (or HPIB?) chain
> to be switched from one computer to another.
> Note that this still requires the same software that #1 and #2 do.
>
>Stan Sieler [log in to unmask]
> http://www.allegro.com/sieler.html
To this let me add:
The ability to SHARE I/O devices between systems. Not just
tape drives, or switching disks from system A to B, but true
shared devices. I believe this may be possible with the new EMC
drives (in a fashion), but the ability to have the same set of data
available to multiple systems concurrently can make a great data
server environment. The concept is not new, IBM has had shared
DASD for a long time, and it's not without risk. You loose the drive,
and you potentially have multiple systems out of action. Those issues
can (for the most part) be overcome with mirroring and RAID though.
The same applies to tapes (several vendors can offer this sort of
setup using a server system today), printers (again third parties or Jet
Direct cards and MPE/iX 5.5),etc. In my ideal setup, I have "devices"
hanging off a high speed network, and CPU's are just another "device".
Sorry for straying a bit there, but I was impressed when I saw my first
Teradata system years ago and thought "why doesn't everyone do disks
that way?" I've been a believer ever since.
Regards,
Michael L (Perception is more important than Reality) Gueterman
Easy Does It Technologies
email: [log in to unmask]
http://www.editcorp.com
voice: (509) 943-5108
fax: (509) 946-6179
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