raistlin@litle.UUCP (Kevin P. Burke) (12/04/89)
this is the summary of responses I recieved from my question I posted last
week on pyramid vs sequent.
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We chose our Pyramid at a time (around 1985) when there
were few choices for a Unix super-mini. We wanted:
1. Unix (BSD)
2. "Lots" of disk capacity
3. "Mainframe" mentality (reliability, support, power,
networking)
4. a company that was committed to forefront technology
5. NFS and network support (Pyramid was one
of the first non-Sun licensees of NFS)
6. Good I/O (disk, tape and tty)
7. Good database support
8. General timesharing mixed with network server support
9. Good field support
10. Good remote technical assistance
11. A platform that could be expanded easily
I think Pyramid has does a creditable job in these areas.
Lately, I have been somewhat disappointed with the remote
technical assistance. And, they have dropped a bit in my esteem
as far as keeping up with the forefront of networking technology
(due to their re-defining their company goals). But I still think
that they do a good job in all of the above areas.
In the past few years we have upgraded our original 90x to
a 98x (2 processors) and now to a 9825 with minimal problems.
I think they have a solid hardware base to build on. I have
been very pleased with the reliability of the machine and the
level of service from our field support engineers.
In comparison to Sequent (a separate division of our company
has a Sequent), I think Pyramid excells in:
1. I/O (Is Sequent still using the Multibus? Ugh)
2. Networking support (Sequent has had some known and
terrible problems with their ethernet).
3. Unix implementation
4. Tty support (their ITP's are very good multiplexors)
5. CPU speed (on a per-CPU basis)
Pyramid's virtual disk strategy is excellent from the standpoint
of reliability, extensibility and flexibility.
Of course, Sequent can offer more processors per box, and
if that is your primary requirement, then Sequent might
be a good choice. But on most other counts, I would choose
Pyramid over Sequent.
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sequent with six CPUs blows away a 1 CPU pyramid but I'm not
uptodate with the money situation.
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I was at a company that made a choice between Pyramid and Sequent, but
I left the company before the decision was made, so I can't offer much
insight from that point of view. Prior to my current position, I was
an employee at Pyramid, and still have some friends who work there.
From that biased perspective, I'll say that I think their software is
very high quality and that the dual universe seems to work great for
applications and end-users.
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For what it's worth, I gather that Sequent machines are cheaper and may
have a slight edge in hardware reliability. Both systems have a fairly
linear speedup as you add more processors. Pyramid machines have much
faster disks and a richer set of disk partitioning strategies, which
means that it's possible to add more disks and get a linear speedup in
disk access. Pyramid OSx is newer (a port of both SVR3 _and_ 4.3BSD)
and more robust. Sequent's Dynix is older, based on SVR2. Their next
O/S release is likely to be an SVR3 port, while we're working on (and
in fact have demoed) an SVR4 port.
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The main difference to consider, in my opinion, involves the
the difference in the compute power of the individual CPUs.
Consider a single user on the system with one active process.
This process will get all of one cpu and on the Pyramid this
is much more processing than that user will get from one Sequent
CPU. On the other hand, one user can 'hog' the system to a greater
extent on the Pyramid than on the Sequent as this is the other
side of the same coin. If you want to limit the share of the system
available to any individual user then the Sequent design makes more
sense, however, on a lightly loaded system the Pyramid can provide
that user with much more processing power.
The Pyramid is also very good at offloading I/O to smart peripheral
processors so you actually get better performance than the CPU
ratings would suggest.
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Price/Performance: Varies from new product to new product. Pyramid has the
edge at the moment. This may change when Sequent ships their 80486 box.
Overall Performance: The Pyramid MIServer has the clear edge on I/O through-
put, especially tty and datacomm, and floating point. The new 80486 Symmetry,
when available, will have the edge on integer CPU performance, assuming you
can achieve the necessary parallism. (Pyramid uses fewer, larger CPUs.) The
Pyramid is a vastly superior box as a network server, whether you are talking
Ethernet, X.25, or IBM protocols; Sequent's NFS is appallingly slow. On the
other hand, a Sun 4/280 is a better NFS server for small networks than either
Sequent or Pyramid.
Reliability: Sequent's hardware reliability is legendary, especially in the
old Balance line, but also in the Symmetry. Pyramid has had trouble with QA
from time-to-time. The MIServer line is much better than the Series 9000.
Service: With Sequent, you better hope it doesn't break, since service is
third party. For software support, you pretty much have to publically berate
them on USENET to get anything fixed. Pyramid has it's own service network,
and software support is very good overall. But it's more expensive.
Software: Sequent's Dynix is old, tired, and crufty 4.2BSD, with a few random
bits of SVR2 and very few random bits of 4.3BSD (notably the tty driver, which
is necessary to support X11R3). OSx is almost all 4.3BSD-tahoe and SVR3.2.
Applicability to your environment: This is a much harder, and much broader
issue. Universities have bought more Sequents than Pyramids, partly because
the initial purchase price was usually lower, and even more so because the
maintenance is much cheaper. Universities also tend to have a cheap labor pool
available to replace half the operating system and turn it into something that
is usable. Commercial sites, on the other hard, generally buy Pyramids. They
are more concerned about maintenance (that is, they are more concerned about
who is going to fix it when it breaks, rather than how often it breaks), and
expect the machine to have reasonable software on it in the first place. There
are variations, of course. Sites running turnkey Oracle applications, for
example, don't care about the underlying OS, since they don't see it. Sequent
has made a strong move into commercial sites lately, largely because of their
powerful sales force and Pyramid's late delivery of the MIServer.
Note: Sequent has, without a doubt, the slimiest sales force in the entire
computer industry.
If you want to do parallel processing, the Symmetry will be better, although
neither machine is really intended for that purpose.
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Business deals aside, two reasons our company chose the Pyramid over the
Sequent were:
1) A lot more MIPS per CPU, which is important when you consider that
a single program can run on exactly 1 CPU at a time; and
2) Support for mirrored disks. We're using this feature with the
latest Informix Turbo RDBMS.
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We chose the Sequent due to a more standard processor, a more open
architecture and software, and what we felt was a better history
of reliability.
We now have a 6 processor Sequent S27. Two minor hardware problems, both
easily and quickly fixed. Many happy users. Wonderful box.
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We have two pyramid's which are unusable -- sitting in the machine
room, unable to boot mutiuser unix. We have a sequent which stays up
for as long as the ups power holds (months at least), and hasn't been
down for more than a few hours at a time for service.
You might benefit from more responses about hardware service. We have
had good (timely and effective) hardware response from sequent. I
have personally called in software bugs and gotten them resolved very
quickly.
We have a 20 processor symmetry. It works very well.
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Here's why we chose Sequent: 4.2BSD Based unix with SysV features
available (Dynix allows users to select "universe").
We've found that it's a good implementation, and a solid system (read
no problems in 2 years in a research environment).
On the down side, Sequent has been slow to implement 4.3 enhancements
into Dynix, appears to be implementing SysVr3 instead of r4 (don't know
why.
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As a thought, have you looked at an Encore Multimax? The machine is a
shared memory symmetric multiprocessor, very similar to a Sequent. The
original products from Encore and Sequent were based on ns32032s, and
were even closer. Today, Sequent offers 386s (4Mips each) and Encore
offers ns32532s (7Mips each).
As for comparision of a Encore/Sequent class machine to a Pyramid;
most companies providing multiprocessors these days are only toying
around with sticking a few (4?) processors together in a box. In most
instances, their OS runs these CPUs master/slave; Pyramid may have "fixed"
this by now. Encore and Sequent both started out by making UNIX run
symmetrically over all the processors in the box - this was long before
DEC touted the term "SMP". The nice thing about the Sequent and Encore
is that you can continue to add CPU cards - adding 2 386s or 2 532s -
and adding more MIPs. With a Pyramid, you can only add 4 - and then
you need to scrap all those old CPUs and buy the next generation.
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We currently have a Sequent S27 in house. For various reasons
(political), Pyramid wasn't considered when we bought it. One
good thing about it is that it hasn't ever gone down in the
year and a half that we've had it. We've had no problems at all
with the Sequent. This is by far its best selling point to us
because all of the nervous managers really like this fact.
One good thing Pyramid offers is up to 16 ethernets. We need to
connect via our Starlan, many many workstations to the machine.
We don't really think the 4 ethernets offered by Sequent will
do the job.
Also, the 386 chip used in the Sequent doesn't really seem to be
much of a match for the RISC chip in the Pyramid. Sequent will be
going to the 486, but they said that the 486 won't come until
about a year from now.
The multiple bus architecture offered by Pyramid also allows you to
fully load each of the components of the machine. You can have the
maximum amount of CPU's, the maximum number of disk controllers, the
maximum number of ethernets, etc. Even though Sequent allows you up
to 30 CPU's on the S81, you have to play board swapping games because
you can't have the maximum memory with the maximum number of CPU's with
the maximum number of ethernets, etc.
One thing that concerns me a little about Sequent is how long it will
take them to have V.4 Unix. Pyramid was running V.4 at the UNIX expo
so I wouldn't think it would take too long for them to have it.
On the low end, Sequent seems to me to have the best cost/performance
rating because of the initial cost of Pyramid's Corporate MIServer.
For the high end (including mucho CPU power, a lot of disk space,
many ethernets, etc) Pyramid has the advantage because you would need
2 Sequent's to give you the same power and capacity as one Pyramid.
In summary, both of these machines seem to be *VERY* good. Our decision
will be based primarily on what we decide our capacity needs are, and
also our comfort level with the reliability of the machines. We are
going to try to do some additional research with Pyramid customers to
discuss the reliability of their machines.
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We were interested in System V compatibility, speed (as a database machine),
expandability, MTBF, and *useful* customer service. Mgmt. was initially
sold on DEC and benchmarked Pyramid/Sequent as an afterthought. However,
we were apalled at DEC's total lack of knowledge about Unix. We spoke
to their Customer Service people, and it was as bad as anything I can
remember.
Pyramid's customer service department actually gave me the feeling that they
knew more about Unix than I did. Sequent wasn't bad as well. Not quite
as good as Pyramid, but good nonetheless.
System V compatability was a big requirement for us. I put together a
benchmark that gave a reasonable mix of our data processing activities.
Sequent was not able to run it, DEC wasn't able to run it, Pyramid ran it
easily. We were able to port the Sequent/DEC versions over several weeks,
and the final benchmarking times/stats showed that Pyramid came out
first, Sequent second, and DEC a very poor third. (BTW this was between a
Pyramid 9825, Sequent Symmetry (4,6,8 processors), and a DEC 6350)
Our benchmark was a combination of scripts, c programs (with informix
database calls), and informix 4gl stuff. Very much single-threaded
processes.
The Sequent won on expandibility. I think that they have a great
machine. They expect to go over to System V.4 soon, and I think that
that will be better than their dual-universe.
One thing that Sequent didn't win on was salesmanship. Their final
report was an exercise in covering their butts on why they weren't
going to get our business. Face it, calling a customer's application
"stupid" is not the way to make a sale. It was, but that's not their
place to say! :-)
We went with Pyramid because of their price, performance, SysV
compatibility, and unix knowledge, in the end.
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We have a Sequent Balance 8000, and a Pyramid 98X. The Sequent has no
maintenance contract while the Pyramid does. So making a comparison on
support would be like comparing apples and oranges, but I would certainly
recommend getting a mainenance contract on whichever machine(s) you
purchase. The support we get from Pyramid (RTOC) is outstanding, while
the support we get from Sequent, without a contract, leaves little to be
desired. There is one problem with the Sequent which I could mention,
and that is that they seem to drop supoort of products fairly quickly.
We purchased the machine a year ago along with an ADA compiler, and the
compiler is not supported by anyone, even if we wanted to purchase it.
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I have a Nixdorf computer which is a Pyramid 9810 in disguise.
Since we needed to run a Nixdorf product and since Nixdorf sells Pyramid,
we have a Pyramid.
We've been running it for a year now - it's performed very well for us.
Please post your summary.
If you have any more questions, please ask.
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... [ the sequent ] is an incredibly reliable machine --
more so than pyramid. It can be expanded more easily to support increasing
work loads (plug in another processor board). If you expect to have just a
few users on the machine (5-8), then a pyramid might be better because each
user gets a faster processor. However, if you are going to have more users
than that, the sequent would be better because each user is getting a
dedicated processor (or close to it). If you plan on a large number of
users and a large configuration, I definitely recommend sequent because it
will support a large number of users better. While I was at the U of I,
they replaced some pyramids with encore and sequent machines.
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Thanx for your feedback, the information given has been very useful.
I've cut out some redundant information in this summary, so if you sent
something and don't see your verbatim here, it's in here somewhere.
-----
Kevin P. Burke | P.O.B. C26, Hanover, NH 03755
raistlin@litle.COM | +1 603 795 2157
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