[ale] Your Opinion Please: OpenLDAP and Samba Infrastructure

[Jeff Hubbs]

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