From: kbvan!dave@uunet.UU.NET (Dave Van Allen)
Newsgroups: biz.sco.general
Subject: Re: Any Veritas users ????
Date: 7 Nov 92 10:44:34 GMT
Organization: [resent by] The SCOGEN gateway and Propagation Society
Resent-From: mmdf@xenitec.on.ca
Submit-To: scogen@xenitec.on.ca
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Quoting Paul A. Fischer, Sr UNIX Sys Consultant:
> 
> Hi ALL,
> 
> Is anyone using Veritas for SCO?  I would like some feedback on their product.
> 
> ----------------------------------------------------------------------------

SCO based RAID software are my life :-)  I have been through it all and I'll
vote for Veritas. In using everyone elses software based RAID products, no
one comes close to Veritas for overall product stability. I'll try to give
you a quick recap of some of the pro's and cons, IMHO:

Veritas has been OEM'ing their volume manager to the big guys (DG, NCR, Moto)
for years. Far longer than anyone else in this field. The SCO version of VxVM
is their first shrunk-wrapped, internally supported product. It is complicated
to initially understand, the manual is written for device driver programmers
and the options for use are taylored to a bored yet bright SA. But with some
study, you'll find that the complexity makes sense. (Other products, 1776 and
the old Chantal Paragon were much _easier_ to use, initially.) Being in the
business for so long, has helped Veritas build a very stable product.

Veritas for SCO is slow. Even with a well designed stripe, the added layer
of the volume manager causes a sizable reduction in both read and write
performance. (Benchmarks available on request). Veritas, set up as a RAID 0
(stripe, no mirror) array is faster by a good margin than a single disk, with
speed of user reads growing better as more users work the I/O bus. (Single
user speed tests are invalid) If you add a single drive mirror to the the stripe
(RAID 1.5, commonly) performance is cut by a noticable factor as the mirror
can sometimes clog the bus as it waits for requests to complete. (Other
products, like above, are at least twice as fast as Veritas, in a like
configuration).

BUT, Veritas is safe. It is the ONLY safe software based RAID package that I
have ever worked with. Chantal, (now owned by Buslogic) has a beta going on
the 3.2.4 release of Paragon. In Paragons old configuration, the product was
lightning fast, but very unstable. So "mission critical" applications went real
fast and then crashed bad. Worse than a single drive crash. Both Chantal and
1776 have problems in ID'ing which mirror went bad during a crash. Veritas
handles this correctly. No sense, IMO, to have a mirror that won't boot or
that boots the wrong drive with pre-crash old data.

I can give you specifics on how to set up situations where a mirrored system
can confuse the software into thinking all is OK when it's really not, if you
are interested.

I have a number of sites running Veritas and everyone is very happy. I have
had drive failures where the product failed-safe and saved the day. I will
caution anyone, however, to know and understand the product from a disaster
recovery stand-point _before_ installing it on your customers. I mean _any_
RAID product.

In fairness to Chantal (whos old product burned me real bad), their new
release of Paragon for 3.2.4 (beta) is looking pretty good, but I will be
twice shy on this one. 1776 has also come a long way, but they still have
a few problems. I am told as recently as today, that they are working on 
them and will have them licked soon. The big pro on 1776 and Paragon is
speed (both replace the stock SCSI drivers with high performance models)
Veritas uses the SCO drivers. But as I said, speed is no good if the array
is down.

So in summary, Paul, it's been my experience that Veritas can be safely
recommended to clients, serves the purpose adiquately, and requires little
consultant maintenance. It handles raw filesystems properly (good for Oracle
users) and can be configured and reconfigured while the system and users
are on-line. For acceptable performance you must run fast SCSI I/O and 
multiple host adapters, but other than that you make no change to the user
or OS platform to have the product on line.

Hope this helped. 

-- 
David Van Allen - Lehigh Software Systems, Inc.
dave@kbvan.COM                   (215) 366-9130
73530,2463 CIS    ************   info@kbvan.COM
uunet!kbvan!dave                  Allentown, PA
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