| Author |
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Walter Roberson
Guest
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 Posted:
Fri Mar 04, 2005 3:00 am Post subject:
Re: 120 Hosts Running GigE at Wire Speed Minimum Cost |
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In article <ZJydnU463Jm1G7rfRVn-qQ@portbridge.com>,
David Ross <news02@raleighthings.com> wrote:
:> Just a comment but Consumer Reports as a matter of policy buys everything
:> they test through the normal purchasing channels,
:And if they buy rev 2 because where they bought is the last part of the
:country to get the rev 3 units, it's worse than useless.
CU deliberately spreads their buying across the country.
--
Will you ask your master if he wants to join my court at Camelot?! |
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Walter Roberson
Guest
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| Posted:
Fri Mar 04, 2005 3:01 am Post subject:
Re: 120 Hosts Running GigE at Wire Speed Minimum Cost |
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In article <XfOdndLTNv6RGrrfRVn-og@portbridge.com>,
David Ross <news02@raleighthings.com> wrote:
:Almost like the old mainframe days
:when IBM and others (some still do) made you sign licensing agreements
:where you would never make public any benchmarks you might do.
Microsoft's .NET EULA has a clause to that effect.
--
Sub-millibarn resolution bio-hyperdimensional plasmatic space
polyimaging is just around the corner. -- Corry Lee Smith |
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Randy Howard
Guest
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| Posted:
Fri Mar 04, 2005 3:42 am Post subject:
Re: 120 Hosts Running GigE at Wire Speed Minimum Cost |
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In article <XfOdndLTNv6RGrrfRVn-og@portbridge.com>, news02
@raleighthings.com says...
| Quote: | So, what to do? If you plan on buying a dozen 24 port switches,
pick one you think does what you need at a decent price, buy
ONE of them from someplace with a reasonable return policy, and
put it through a trial by fire for a few weeks with everything
you can think to throw at it. If you do multicasting, then
send as much of that through it as you can. If you think you'll
be running the switch wide open, then do that. I've seen
switches reboot due to firmware bugs when performance counters
overflow internally. So send it long streams of data, for days
or weeks and make sure it doesn't roll over. If it makes it,
order 11 more. If not, return it and start over.
HP is having a 30 day return policy for up to 2 of some models of their
switches just now. I need 4 for one office but am buying 2 just to run
them through their paces before I jump in with both feet.
|
An excellent plan. Be sure to run all ports in parallel, not just
test a few of them at a time. Obviously, for this to work best, you
need stress and performance measurement software than can achieve
wirespeed (and hardware fast enough to get there). To verify this,
take two fast systems. Put them on any pair of ports by themselves.
If you cannot achieve 125MBytes/s one way (ram to ram) between
the machines, or something in the neighborhood of 200-220 MBytes/s
FDX (ram to ram) between those two systems, then you don't have the
right test software, the right hardware, or both. (BTW, you should
be able to get the same exact numbers just using a direct connection
between the two systems if you suspect the switch is a problem).
If you get that working, then try these types of tests:
[ I am going to pretend like they are only 4 port switches just to
make this easier to explain. Extending it to 16, 24, 48, etc. is
trivial ]
Switch
P1 P2 P3 P4
S C C C (S=server, C= client)
BTW, when I say client, I mean in the TCP sense, not in the "slow
desktop" sense.
Put a server on P1, and have p2, p3 and p4 all send and receive (in
parallel if possible) simultaneously to P1 and make sure it doesn't
start clamping down as clients are added, all being funnelled into 1
port. For larger switches, they are often split logically
internally, with two "half switches" that communicate through a
higher speed interconnect. Example, a 24-port switch may be to 12-
port switches ganged together. Usually this is done logically, so
that 1-12 are on one "side", and 13-24 are on the other. Make sure
that you measure throughput with all clients on the same "half" of
the switch, and on the opposite "half" and you get equivalent
results. You also may want to have multiple servers, say one or two
on each half, with clients funneling into them from the same, or
opposite sides of the switch and verify that performance doesn't
drop off.
Next, set up your switch like this:
Switch
P1 P2 P3 P4
Ca Cb Cc Cd
Run traffic (FDX if possible) between pairs of ports. Ca <-> Cb,
Cc <-> Cd, etc. By doing this, if the switch is truly non-blocking,
you should not see the individual pairs slow down, even with all of
them running wide open.
If you care about multicast, then you want to try this as well, were
you generate on one port, and subscribe from some small subset of
the other ports. Verify (if it support IGMP) that *only* the ports
that are subscribed are getting the traffic. Do this by having the
non-subscribed ports sit idle so you can easily tell if the switch
starts flooding by looking at the traffic lights.
Also, during all of the above scenarios, when the switch is under
high load, attempt to manage the switch (assuming it is a managed
switch) via an ethernet connection, or via the serial port. If the
management interface doesn't essentially cease to respond during
wide open tests, particularly multicast tests, that is rare.
If it is a stackable switch, you want to extend the above to put
as much traffic across the stack links as possible.
If it supports VLANs, and all the other goodies, there are endless
variations and additional items to test. The ones above are
important, I have seen some less than wonderful switches actually
start randomly dropping links when the traffic levels on all
the ports are near wirespeed.
Also, make sure you throw in some 100mbit and 10mbit (if that's
a possibility) into the mix to make sure it handles that properly.
This is by NO means an exhaustive test as described above, but it
does represent a very important (and often omitted) set of test
cases for a much larger full test of a switch. Many of the
switches on the market today would never have made it out the
door in their present form if these tests had been run on them
before their RTS date.
| Quote: | I'm looking at about $10k total. I can just imagine the sale FUD if I
was looking to spend $250K or $2.5M. Almost like the old mainframe days
when IBM and others (some still do) made you sign licensing agreements
where you would never make public any benchmarks you might do.
|
Because they didn't want to take the risk that their next customer
might find out that their hardware was slower then the next guy's.
--
Randy Howard (2reply remove FOOBAR)
"Making it hard to do stupid things often makes it hard
to do smart ones too." -- Andrew Koenig |
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David Ross
Guest
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| Posted:
Fri Mar 04, 2005 5:31 am Post subject:
Re: 120 Hosts Running GigE at Wire Speed Minimum Cost |
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| Quote: | HP is having a 30 day return policy for up to 2 of some models of their
switches just now. I need 4 for one office but am buying 2 just to run
them through their paces before I jump in with both feet.
An excellent plan. Be sure to run all ports in parallel, not just
test a few of them at a time. Obviously, for this to work best, you
need stress and performance measurement software than can achieve
wirespeed (and hardware fast enough to get there). To verify this,
|
I don't know that I have time (or the client's dimes) for all you
suggest. To some degree we're future buying. These things will be 1/2
the size of the HP 4000s they'll replace and due to an office
rearrangement we now have 4 clusters of "stuff" vs 3 in the past. If
nothing else I plan to do a server to server duplication of the 40,000
word, excel, cad, photoshop, etc... files, run a backup to tape, and
have 1/2 the remaining watching videos from the internet with the rest
watching movies off another server. Just to see if the switches will
crash. This should deal with our "normal" load for a while. Each of the
things I mentioned will move data across the network and I'll do it so
that one run pounds the switch to switch setup while the other stays in
the switch. Then I'll move on to some of the other setups you mentioned.
It's hard to find the time to test VLANs past what we plan to do. As you
noted.
:) |
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David Ross
Guest
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| Posted:
Fri Mar 04, 2005 5:33 am Post subject:
Re: 120 Hosts Running GigE at Wire Speed Minimum Cost |
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Walter Roberson wrote:
| Quote: | In article <ZJydnU463Jm1G7rfRVn-qQ@portbridge.com>,
David Ross <news02@raleighthings.com> wrote:
:> Just a comment but Consumer Reports as a matter of policy buys everything
:> they test through the normal purchasing channels,
:And if they buy rev 2 because where they bought is the last part of the
:country to get the rev 3 units, it's worse than useless.
CU deliberately spreads their buying across the country.
|
But their dependence on single point per model or even manufacturer
means a good shopper treats CU the same. As a single point of data in
the buying experience.
And let's not even get into the "political bias" they bring into their
"unbiased" testing. What you test FOR and how you weight the tests is a
major bias they don't discuss. |
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David Ross
Guest
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| Posted:
Fri Mar 04, 2005 5:52 am Post subject:
Re: 120 Hosts Running GigE at Wire Speed Minimum Cost |
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| Quote: | :Almost like the old mainframe days
:when IBM and others (some still do) made you sign licensing agreements
:where you would never make public any benchmarks you might do.
Microsoft's .NET EULA has a clause to that effect.
|
For those old folks around here, remember when the weekly rag,
(ComputerWolrd?), had an ad every week showing SyncSort wiping out IBM's
sort. After a few years, IBM posted some ads showing how they had bested
SyncSort. Then it came out they had rigged the results. Not just a tad,
but by a huge disparity in how the tests were run. Several folks at IBM
got spanked over that one.
For those who don't know these references, it's from the late 70s, early
80s. |
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J. Clarke
Guest
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| Posted:
Fri Mar 04, 2005 8:01 am Post subject:
Re: 120 Hosts Running GigE at Wire Speed Minimum Cost |
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David Ross wrote:
| Quote: | Walter Roberson wrote:
In article <ZJydnU463Jm1G7rfRVn-qQ@portbridge.com>,
David Ross <news02@raleighthings.com> wrote:
:> Just a comment but Consumer Reports as a matter of policy buys
:> everything they test through the normal purchasing channels,
:And if they buy rev 2 because where they bought is the last part of the
:country to get the rev 3 units, it's worse than useless.
CU deliberately spreads their buying across the country.
But their dependence on single point per model or even manufacturer
means a good shopper treats CU the same. As a single point of data in
the buying experience.
|
They seldom provide a "single point per manufacturer". In most tests there
are multiple models by a given manufacturer and they also have owner-survey
results.
| Quote: | And let's not even get into the "political bias" they bring into their
"unbiased" testing. What you test FOR and how you weight the tests is a
major bias they don't discuss.
|
Their methodology is another story. Sometimes it's good, sometimes it's
not.
--
--John
to email, dial "usenet" and validate
(was jclarke at eye bee em dot net) |
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Randy Howard
Guest
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| Posted:
Fri Mar 04, 2005 6:32 pm Post subject:
Re: 120 Hosts Running GigE at Wire Speed Minimum Cost |
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In article <d08rrp01915@news1.newsguy.com>,
jclarke.usenet@snet.net.invalid says...
| Quote: | And let's not even get into the "political bias" they bring into their
"unbiased" testing. What you test FOR and how you weight the tests is a
major bias they don't discuss.
Their methodology is another story. Sometimes it's good, sometimes it's
not.
|
One only has to look as far as their legal loss in court to Bose over
them actually having the temerity tp post a legitimate evaluation of
the horrific frequency response characteristics of a particular model
of Bose speakers, and then the subsequent 100% laudatory remarks upon
Bose products after that legal disaster to realize they are not worth
reading.
"If you sue us, we'll give you a good review, even though your
product is abysmal."
--
Randy Howard (2reply remove FOOBAR)
"Making it hard to do stupid things often makes it hard
to do smart ones too." -- Andrew Koenig |
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Randy Howard
Guest
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| Posted:
Fri Mar 04, 2005 6:33 pm Post subject:
Re: 120 Hosts Running GigE at Wire Speed Minimum Cost |
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In article <9JudnSSdI-LHLLrfRVn-gQ@portbridge.com>, news02
@raleighthings.com says...
| Quote: | :Almost like the old mainframe days
:when IBM and others (some still do) made you sign licensing agreements
:where you would never make public any benchmarks you might do.
Microsoft's .NET EULA has a clause to that effect.
For those old folks around here, remember when the weekly rag,
(ComputerWolrd?), had an ad every week showing SyncSort wiping out IBM's
sort. After a few years, IBM posted some ads showing how they had bested
SyncSort. Then it came out they had rigged the results. Not just a tad,
but by a huge disparity in how the tests were run. Several folks at IBM
got spanked over that one.
For those who don't know these references, it's from the late 70s, early
80s.
|
You don't have to go back that far. Remember Apple cooking the
results for G5 performance by using different compiler optimization
settings and hoping that nobody would verify their results? That
was just a couple years ago, IIRC.
--
Randy Howard (2reply remove FOOBAR)
"Making it hard to do stupid things often makes it hard
to do smart ones too." -- Andrew Koenig |
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J. Clarke
Guest
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| Posted:
Fri Mar 04, 2005 9:41 pm Post subject:
Re: 120 Hosts Running GigE at Wire Speed Minimum Cost |
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Randy Howard wrote:
| Quote: | In article <d08rrp01915@news1.newsguy.com>,
jclarke.usenet@snet.net.invalid says...
And let's not even get into the "political bias" they bring into their
"unbiased" testing. What you test FOR and how you weight the tests is a
major bias they don't discuss.
Their methodology is another story. Sometimes it's good, sometimes it's
not.
One only has to look as far as their legal loss in court to Bose
|
What "legal loss in court to Bose is this"? If you are referring to the
1983 case then Consumer Reports took it to the Supreme Court and whupped
Bose's ass.
| Quote: | over
them actually having the temerity tp post a legitimate evaluation of
the horrific frequency response characteristics of a particular model
of Bose speakers, and then the subsequent 100% laudatory remarks upon
Bose products after that legal disaster to realize they are not worth
reading.
"If you sue us, we'll give you a good review, even though your
product is abysmal."
|
Now why would they want to give Bose good reviews after they spent all that
money securing the right to give them bad ones?
--
--John
to email, dial "usenet" and validate
(was jclarke at eye bee em dot net) |
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David Ross
Guest
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| Posted:
Fri Mar 04, 2005 10:53 pm Post subject:
Re: 120 Hosts Running GigE at Wire Speed Minimum Cost |
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| Quote: | For those old folks around here, remember when the weekly rag,
(ComputerWolrd?), had an ad every week showing SyncSort wiping out IBM's
sort. After a few years, IBM posted some ads showing how they had bested
SyncSort. Then it came out they had rigged the results. Not just a tad,
but by a huge disparity in how the tests were run. Several folks at IBM
got spanked over that one.
For those who don't know these references, it's from the late 70s, early
80s.
You don't have to go back that far. Remember Apple cooking the
results for G5 performance by using different compiler optimization
settings and hoping that nobody would verify their results? That
was just a couple years ago, IIRC.
The interesting thing about the SyncSort episode was that ComputerWorld |
(?) was read by nearly EVERYONE at the time and there seemed to be a
different ad each week showing a different trouncing of IBM sort by sync
sort. And this went on for YEARS. Literally years. That ad series ran
longer than the life span of most software these days. :) |
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Hansang Bae
Guest
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| Posted:
Sat Mar 05, 2005 8:02 am Post subject:
Re: 120 Hosts Running GigE at Wire Speed Minimum Cost |
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Randy Howard wrote:
| Quote: | You don't have to go back that far. Remember Apple cooking the
results for G5 performance by using different compiler optimization
settings and hoping that nobody would verify their results? That
was just a couple years ago, IIRC.
|
Or the unamed video card vendor who put the PC Magazine benchmark into
hardware. That was pretty funny. "WOW..this card is out of this
world!" "Wait...why, then, does it blow chunks in real world apps.."
--
hsb
"Somehow I imagined this experience would be more rewarding" Calvin
**************************ROT13 MY ADDRESS*************************
Due to the volume of email that I receive, I may not not be able to
reply to emails sent to my account. Please post a followup instead.
******************************************************************** |
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James Knott
Guest
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| Posted:
Sun Mar 06, 2005 12:09 am Post subject:
Re: 120 Hosts Running GigE at Wire Speed Minimum Cost |
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Hansang Bae wrote:
| Quote: | Or the unamed video card vendor who put the PC Magazine benchmark into
hardware. That was pretty funny. "WOW..this card is out of this
world!" "Wait...why, then, does it blow chunks in real world apps.."
|
That also used to be a favourite trick with mother boards. Another was
"Winmarks". Someone would compare their 386 system to a 6 MHz IBM AT with
a 286 CPU and find it ran (for instance) 20 times faster. They'd then
claim they had a 120 MHz CPU! |
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