[K12OSN] 2-server setup

[Burke Almquist]

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I'd say once you get beyond the one off deployment you'd want at  
least three boxes.
Ideally I'd want the storage of /home and your authentication  
functions on a separate server from the LTSP servers for a couple of  
reasons.

1. It's easier to scale this way.
and
2. The needs of the file and authentication server are fundamentally  
different than that of an LTSP server.


Leaving /home and LDAP on a separate machine (with fast SCSI RAID)  
lets you put all the expensive storage (and the important information  
that needs backup) on one machine. The NFS/LDAP servers need  
reliability and fast storage primarily, not speed, to do their job.  
That means SCSI RAID, maybe even hot swap and redundant power  
supplies.  Think main file server here.  Your NFS/LDAP server  
achieves reliability by building redundancy into the machine with  
RAID, a UPS, hot swap features, redundant power supplies, etc. This  
also makes scaling up easier. This machine scales up by adding RAM  
and disks (so start with SOME extra cpu, just not as much as a  
monster LTSP server maybe).

The LTSP servers OTOH don't need that kind of storage. Think of them  
as a screaming workstation. Lots of CPU and RAM. These scale up by  
increasing the quantity. You can have many relatively cheep and  
almost identically configured servers. This also lets you isolate  
network traffic also by not putting too many clients on one gigabit  
connection.


On Jan 30, 2007, at 12:52 PM, Krsnendu dasa wrote:

> I guess putting /home on its own machine would also provide a
> performance benefit too.
> Is this right?
>
> On 31/01/07, David Hopkins <dahopkins429 at gmail.com> wrote:
>> The only 'gotcha' with using just two servers is that if you  
>> upgrade the
>> server that is hosting /home and also is the LDAP master, it is  
>> more tedious
>> and (in my view) more a pain since you have to potentially setup  
>> LDAP again,
>> and make sure that /home isn't lost.  I guess you could  
>> redesignate the LDAP
>> master to the server you are not upgrading as well as moving /home  
>> to it,
>> and switch their roles. I use a server which is dedicated to  
>> hosting /home
>> and running as the LDAP master.  Then, my K12LTSP servers are LDAP  
>> slaves
>> (thanks to the wonderful script supplied by Matt Olmquist (?) and  
>> David
>> Trask).  This way, upgrading the K12LTSP servers is relatively  
>> risk free in
>> the sense that if K12LTSP installs, then you are almost done once  
>> you copy
>> over all of the conf (dhcp, cups, ltsp) files that you needed to  
>> save.
>>
>> Sincerely,
>> Dave Hopkins
>>
>>
>>
>>
>> On 1/29/07, Todd O'Bryan <toddobryan at mac.com> wrote:
>> > On Tue, 2007-01-30 at 08:42 +0530, Sudev Barar wrote:
>> > > On 30/01/07, Todd O'Bryan < toddobryan at mac.com> wrote:
>> > > > mostly to have one in case the other dies. How hard is it  
>> going to be
>> to
>> > > > set up one as an LDAP server and remote mount its /home on  
>> the other
>> > >
>> > > Just to mention...not very hard at all. And you will also have to
>> > > setup LDAP with master slave configuration on two servers.
>> >
>> > Thanks for the reassurance. That's my project on Wednesday.
>> >
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