Server Best Practices --

Tue Feb 10 17:34:10 UTC 2009

On Feb 10, 2009, at 10:03 AM, Patton Echols wrote:

>>> Project 2. Setting up a Samba server so that the in house Windows
>>> users have lan based redundant  (RAID-1) storage / backup area.
>>>
>>> Project 3.  Allowing server to function as remote site for my office
>>> automatic backups.
>>
>> I would lump Projects 2 and 3 together, as they sort of have the same
>> basic purpose, file-storage.  Obviously, you'd want to make sure that
>> whatever firewall you have this server behind (or local firewall, if
>> it's not behind a separate firewall) is blocking access to Samba from
>> the Internet.  As for your office backups, how you would implement
>> being a remote site is probably dependent on the requirements of your
>> backup configuration.  I would not recommend just backing up over an
>> exposed SMB/CIFS share, it's just asking for trouble.  If you do want
>> to back up to an SMB/CIFS share over the internet, I would suggest
>> doing it over a VPN (which would be another project in and of  
>> itself).
>
> Right, I had thought that one of the two servers would contact the  
> other
> via ssh and then backup using rsync

Yeah, rsync over ssh for your backup would be fine over the internet.

>
>
>>
>>>
>>>
>>> Project 4.  LTSP server both to serve Ubuntu desktops and w/ a
>>> virtual machine to serve XP desktops.  (The boxes that would be  
>>> using
>>> this all have their own licenses.  But the hardware was never really
>>> adequate and by today's standards pathetic).
>>>
>>> The machine currently redundant and tapped as the probable server is
>>> a Celeron 2.4 ghz w/ 1.6 Gb RAM.  Ideally I'd like to just add the
>>> drives required to support the necessary storage, possibly more ram
>>> and get started, one thing at a time.
>>
>> Judging from your current system configuration, it is possible to use
>> it as an LTSP server.  However, you'd have to give more information  
>> as
>> to how many clients you're expecting to serve.  The number of clients
>> you're planning on having connect to your LTSP server will determine
>> what your hardware needs are.  Here's a reasonable place to get a
>> ballpark for what you'd need:  http://www.k12ltsp.org/install.html
>
> Based on that, it could work.  I am only planning 3 or 4 clients, and
> the anticipated workload is low.  That site also mention using the  
> LTSP
> server as "cable modem gateway/firewall and household terminal/file
> server. "  But your security concerns are well considered.

OK, yeah, then your hardware should be sufficient.  I'd still suggest  
bumping up the RAM to as much as you can.  Remember, each application/ 
process will take a chunk of available memory.  The user-land programs  
you'd be serving up over LTSP will probably be the biggest users of  
RAM, especially (as mentioned in the link) Firefox.  Unfortunately,  
Firefox and Thunderbird tend to be memory hogs, and FF does have a few  
memory leaks (although, a good number of them have been fixed in the  
3.0.x branch).  Thunderbird does as well.  Ultimately, you'll want to  
have enough RAM in your system to keep swapping to a minimum.  You'd  
probably be fine to try your current set-up and increase the amount of  
RAM if you start noticing heavy swap activity.

Obviously, as with any Linux installation, be sure to disable any  
services you're not using in order to conserve resources for the  
services you are using.

>
>
>>
>> Please keep in mind that those hardware requirements are for a server
>> that is SOLELY serving as an LTSP server with no other function.   
>> LTSP
>> is pretty resource intensive on the server-end, as all applications
>> technically run on the server and not on client.  The more users you
>> have and the more applications they have open at the same time, the
>> more strain is placed on the server.
>>
>> In light of that, adding a Windows Server (running Terminal Services
>> or Citrix) in a VM on the same server would be very taxing.
>
> Oh . . . Not what I thought.  I had thought I had read  somewhere that
> you could have a VM that delivered an XP desktop without the necessity
> of running Windows server.  Not so?  This part of the project is  
> purely
> hobbyist stuff and not worth the expense of licensing windows
> server/terminal services

This may be possible, but I personally haven't heard of it.  It would  
be interesting if this were indeed possible.

>
>
>> You'd at very least want to be running it on a server with multiple
>> processors or cores and devote 1 or more of the processors / cores to
>> the VM.  You'd also have to dedicate a slice of available RAM to the
>> VM which means it wouldn't be available to the underlying server.  If
>> you're going to be running a Linux / Window terminal server, I would
>> definitely recommend setting aside some dedicated hardware for it.
>> Or, at least bumping the specs up for your current system.
>>
>> Otherwise, it is possible to run Apache and Samba on the same system
>> and have it serving as a LAMP and SMB/CIFS server.  I would advise  
>> you
>> to look into the security implications of doing so, however.  If
>> someone was to exploit a security flaw in PHP through one of your
>> sites, they might be able to gain access to files you have stored in
>> your Samba share or backups.  In the same vein, if someone were to
>> exploit a flaw in Samba, they might gain access to your webroot as
>> well.  Things to think about as you go forward with your endeavors.
>
> Ok, that makes sense.  But access from the outside world has to get
> through a hardware "appliance" router and as long as the only thing  
> that
> gets through is SSH, then I should be ok?

Yeah, if it's behind a firewall and only accessible from the outside  
world via SSH, you should be good.  Just wanted to make sure to point  
out some of the possible security implications of making some of those  
services available on the 'net.  Some people reading this thread now  
or in the future might not think of some of those things right away.

>
>
>>
>> As Rashkae already posted, it is *possible* to do all of these things
>> on one piece of hardware.  I would argue that it's not *practical* or
>> recommended to do so.  But, sometimes you just have to make due with
>> what you have available.  Again, Projects 1-3 on the same server is
>> the most doable scenario.  I would recommend focusing on mitigating
>> security risks while doing so, however.  And for the LTSP / Windows
>> server aspect, you'd need to lay-out some cash whichever way you went
>> with it (upgrade current hardware / purchase new hardware) as your
>> current specs would probably be pretty strained under the load of
>> *all* of those services, especially Project 4.
>>
>> -- 
>> Preston
>
> Thanks again for your thoughts,
>
> Patton
>
> -- 
> ubuntu-users mailing list
> ubuntu-users at lists.ubuntu.com
> Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-users