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John Rodkey wrote:
>
> Current design:
all sounds normal enough.
> Questions:
> Realistic ?
yes
> DR vs. NAT? (The Linux Journal article in April indicated NAT was limited
> to about 1700 tps... we don't approach that volume, but it also looked like
> DR was cleaner. No?)
The people who wrote the Linux J article didn't contact anyone here
(except Wensong to get permisssion to use a diagram),
found some of the simple setups beyond their capabilities
and didn't specify their tests well enough
for me to be able to tell what they had tested
(they were getting hit rates on their approx 500MHz
servers close to what I get on my 75MHz pentium classic
realservers, but since they didn't tell you the hit size,
their numbers were meaningless).
All these problems could have been sorted out before
publication if they'd asked someone who knew how to
setup and test an LVS.
The default is DR mainly for historical reasons, but it's what
you try first for a production setup.
> Can any other services be accommodated by the LVS - e.g.
> DHCP,
> LDAP,
> DNS,
> IMAP,
> SMB
any single port service is trivial. Multiport services (eg ftp)
are best done with fwmark. Don't know much about SMB - how many
ports are involved here?
> What big piles of poo do I need to avoid stepping in?
the arp problem and identd are the major problems. If you understand
that, then you're home
> What would you estimate for amount of time to implement something like
> this? (i.e., 4 LVS RS's, 6 HA servers? - assuming that the setting up
> of the service itself has already been done)
6 HA servers?
> Bottlenecks?
> Where do you need power & memory hungry monsters for servers, and where
> can you do just fine with low-end (e.g. 300MHz Celeron) computers?
The director is just a specialised router. The realservers have to be
able to deliver the expected throughput with say one machine down for
servicing.
> Is it realistic to have the Directors have no hard drive, but boot off a
> floppy with Linux Router Project images? Boot off a CDROM image?
no reason it can't be done. You only need enough to boot the machine and a few
utilities (vi, ls...)
> I see the Directors usually have 2 ethernet cards... Where else would
> multiple cards be highly desirable?
I have quad cards on my director(s). One port to the outside world, one to the
realservers,
one spare (or for HA), one for admin that has ssh listening on it, and which is
not connected
to any other network and which is the only place you can connect to the
director (other
than the console).
> My earlier question about SMB was greeted with "you'll be the first"... is
It's still true :-)
> there a technical reason why SMB wouldn't be possible with the LVS, or is
> there an outside chance my effort could be rewarded?
I expect it should work. Presumably there are SMB experts here who know the
number of ports involved and what they're doing. I don't have any windows
machines here to test with, but if no-one else here leaps forward to fill
you in on SMB, I'd be quite happy to get with you offline and discuss the
matter till you can see your way clear on the subject and make a sensible
decision. It would be nice to have a section in the HOWTO on SMB.
Joe
--
Joseph Mack PhD, Senior Systems Engineer, Lockheed Martin
contractor to the National Environmental Supercomputer Center,
mailto:mack.joseph@xxxxxxx ph# 919-541-0007, RTP, NC, USA
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