Hi,

I'd like to add another caution to the use of the HVD10 disks.  They come
with 9, 18, 36 or 72 gb disks, with 10 to an enclosure.  This means that
you can get up to 720 gb in the space roughly that of a Jamaica.

As most of you know, one of the main majiks about MPE is how tightly
integrated the whole package is.  Hardware, software, operating system,
file system and DBMS (Image) all play very well together (btw, this is true
of other "proprietary" systems as well such as the AS400).  This being the
case, there is a very real, very tangible performance advantage.  Those of
you who have Unix/Oracle (poor, poor souls) experience the relative
differences in performance every day.  I've often heard (maybe because I've
often said :-) that, if one was to take an HP 3000 application running
VPLUS and Image and ported it to Unix under Oracle, it would take
approximately four to eight times the amount of horsepower to function
comparably to the HP 3000 environment.

One of the reasons this is true is because of the wonderful I/O efficiency
the HP 3000 offers.  For example, one of the best I/O performance metrics
on the 3000 is Read Hit Percentage.  This is the number of read requests
satisfied in main memory.  The other side of the coin is that this
indicates what percentage of all physical disk reads are eliminated.  For a
healthy HP 3000 this number is *generally* 95 percent or greater.  (For the
benefit of my friend James Reynolds let me add an "It Depends" here.)

Given the fact that nearly all physical disk reads are eliminated and that
nearly all disk writes are journaled through the Transaction Manager, most
I/O performance problems are removed from the response time of the
individual user.  (As an aside, this is why a health MPE disk environment
won't benefit much from the new whiz-bang disk I/O technologies.  The most
additional physical disk I/O that can be eliminated is in the 5-10 percent
range, not an amount likely to be visible to the end user).

One of the reasons disk I/O is so efficient on MPE is that there is a
significant amount of disk I/O parallelism.  That is, the more spindles you
have, the more each spindle can be concurrently tasked with I/O
requests.  Given that the most heavily accessed files on any particular
system are likely broken into multiple pieces (or "extents") and that these
pieces are likely located on multiple spindles, the I/O subsystem will
generally be multitasking on your behalf.  Add to this the inherent
additional multitasking associated with Mirrored Disk/iX (reads are
"balanced" on both of the mirrored pairs) and you have a wonderfully
efficient I/O environment.

This leads me to the essence of this posting.  The driving technical issues
behind the newer disk technologies do not take into account the so-called
proprietary environments.  IMO the three main driving factors behind these
new technologies are 1) Price, 2) Density and 3) High Availability, not
necessarily in that order.  I believe that these factors are driven largely
by the Unix and Wintel markets, the lowest common denominators of computing
today.

The price and density factors essentially result in fewer and fewer
spindles to spread out your data over.  Given that I/O performance in a
Unix/Oracle world generally, by our standards anyway, sucks (a technical
term) you don't generally perceive such a loss of spindles in that
environment.  (Before some of you Unix heads get upset with me let me add
that this isn't always true.  Just most of the time. :-).  In MPE-land you
experience it pretty dramatically.

That all being said, as you make the sojourn into the nether region of
Unix- and PC-led disk hardware, please, please, please keep in mind that
you have to "care-and-feed" an MPE environments performance
differently.  You must have a care to ensure that you never dramatically
drop the number of spindles you spread your mission-critical data over.  We
are in the process of implementing and HVD10 disk solution for a
customer.  From the beginning we are 1) selecting only the 9gb disks (fast
little critters!) and 2) configuring only 50 percent of the space.  This
allows us to actually have a performance advantage of the customers
existing disk environment by not measurable reducing the spindles and by
having much faster disks.

This may seem wasteful but there isn't much price difference between the
Jamaica 4.3's and the HVD10 9.0 gb disks.

Hope this helps.

Bill Lancaster

At 09:28 AM 08/08/2000, John Painter wrote:
>Jim:
>
>I checked this out on your heads up-- took me by surprise too. The short
>of it is that the RACK mount HASS enclosures are being obsoleted in
>favor of this new HVD10 product that supports faster and bigger disks.
>The DESKSIDE HASS will remain until some future product TBA in 2001
>takes it's place. The HVD10 product is more expensive to buy, but it
>holds more capacity in it's footprint. The kicker is that you need to be
>careful which disks you order under MPE, because some of the disks
>supported in the enclosure are not supported under MPE. Meanwhile, HASS
>parts (disks, fans, power supplies) will be available till mid 2001 and
>there is the standard 5 year support life. There is also the typical HP
>trade in program to move your rack mount HASS out and the HVD10 in.
>
>Hey, what have you bought from HP lately? ;-)
>
>John Painter
>Computer Solutions, Inc.
>http://www.internetcsi.com
>
>
>
>
>Jim Phillips wrote:
> >
> > I read where:
> >
> > "High Availability Storage System (HASS) (A3312A/AZ) Rack Units will be
> > Discontinuance on November 1, 2000. This will be the 6-month notice. The
> > customers are recommend to go to the HP SureStore HVD10 product
> (A5616A/AZ).
> > Please see the ESP and CNO announcement on the HVD10."
> >
> > Just what does this mean?
> >
> > Jim Phillips                            Manager of Information Systems
> > E-Mail: [log in to unmask]     Therm-O-Link, Inc.
> > Phone: (330) 527-2124                   P. O. Box 285
> >   Fax: (330) 527-2123                   10513 Freedom Street
> >   Web: http://www.tolwire.com  Garrettsville, Ohio  44231