[Samba] Domain controller in a chroot

[Sketch]

On Tue, 17 Mar 2015, Sébastien Le Ray wrote:

> Le 17/03/2015 11:06, Sven Schwedas a écrit :
>>  Not really an option : :-)
>>                total       used       free     shared    buffers cached
>>  Mem:           496        470         25          0 58         82
>> 
> I'm sucessfully running a fileserver on it, just wanting to avoid issues in 
> case of network link outage.
> DC overhead shouldn't be that huge since it is only used uppon session 
> opening (we can upgrade memory though)

I upgraded one of my DCs from 2GB of ram to 8GB because it was 
occasionally running out of RAM and crashing, which was not a problem I 
saw on my other DCs with more RAM.  That was earlier in 4.1.x, so it's 
possible memory usage has improved somewhat, but I wouldn't count on it 
running reasonably in 512MB.  Looking at my DCs, they are running 13 
"samba" (not smbd) processes which are around 40MB RSS each.  This is 
clearly not going to work well in 512MB of RAM, especially with anything 
else (such as smbd) running on the machine.  That's not including a DNS 
server, as I use BIND DLZ (which is using another 80MB RSS.

Beyond that, the reason running a DC on a fileserver is considered harmful 
is just because of the built in winbind on DCs in 4.0/4.1.  I believe this 
should be fixed in 4.2.  Also, you can run sssd instead of winbind, which 
will avoid the problem.  So it should be doable if you upgrade the memory, 
but I wouldn't even attempt it without at least 1GB of RAM, preferably 
more.