[ale] Your Opinion Please: OpenLDAP and Samba Infrastructure

[Jim Kinney]

Since you have 'em by the boxload, go ahead and use 4. Especially that
little Nehimia cpu. It's pretty weak and doesn't handle thread
swapping worth poop. With 256 MB RAM you'll likely be into swap space
going back and forth between LDAP and PDC contexts. And swapping to an
SSD is a no-no.

Also, no need to custom compile for processor affinity. The binary
better _LOVE_ that cpu or it's not gonna get any, um, "time in the
chip". :-)

I haven't done a serial port heartbeat since 1998-99. Null modem
cable's are getting scarce! I think I use a scripted netcat that had a
date string and a random number and each end would generate are reply
with an echo. Now there's a heartbeat tool but I think it is ethernet
only.

On Mon, Jun 15, 2009 at 3:43 PM, Jeff Hubbs<jeffrey.hubbs at gmail.com> wrote:
> Jim Kinney wrote:
>> Master LDAP and backup Samba on box A and backup LDAP and PDC on box
>> B. Splits the load better. Be sure to include a dedicated (crossover
>> ethernet) line for server-server sync for LDAP. It can also serve as
>> the heartbeat line.
>>
> Hm, not something I can readily do - I'm using thin clients with SSDs
> because 1) no moving parts 2) we have them by the boxload.  Just one
> 100base-TX port per.  I understand there's some serial-port heartbeat
> action I can make use of, though
>> As for whether it should go to 4 machines depends on the loading. 2GHz
>> single core, 2GB RAM Xeon is supposed to be able to handle many
>> hundreds of thousands of LDAP queries a day (several thousand users)
>> with a schema that can fit all in RAM. By adding the other Samba
>> service, you'll need to double the RAM and go for a dual core cpu to
>> keep that same ability.
>>
> Several hundred but not several thousand per day.
>> If possible, compile both services
> Natch (it's Gentoo)!
>> and include processor affinity
>> flags (LDAP master on cpu0, samba on cpu1 for A and reverse for box
>> B). I have not seen processor affinity make it to a startup flag
>> status yet ( i.e. a /proc entry - that will be _SO_COOL_ if it ever
>> happens! Apparently it's very very hard.)
>>
>> Note: since these services are looking to use RAM caches for data, use
>> AMD Phenom or Opteron systems if possible.
> 1GHz Via Nehemia; -march=c3-2
>> Their memory management is
>> much faster with on-die ram control until. Opteron has much more L2
>> cache than Phenom.
>>
> As long as I'm reading from an OpenLDAP backend that doesn't change
> hugely, I'm not anticipating performance problems.  256MB RAM (minus
> shared video); no swap.  Runs OpenLDAP, Samba, and Webmin at once
> presently.  Disk I/O, however, is crap (apparently no DMA for Cardbus
> yet).  I may still want the headroom of spreading HA OpenLDAP and Samba
> PDC/BDC across four units; that's what I'm trying to decide.
>
>
> - Jeff
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-- 
-- 
James P. Kinney III
Actively in pursuit of Life, Liberty and Happiness