[Thinlinc-technical] More users / Less servers

[Christian Nygaard]

2xNehalem L5520, 48GB in 6 dimm or 12 dimm and swapping to 80GB Intel 
X25-M 34nm SSD should be able to take quite some users, most likely 
throttling out on hang Firefox and Acrobat reader processes. I would
also put the apps on SSD so the server doesn't io stall.

2xThinlinc agents of above
|
|
|Intel 82599 10GE private network link
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1xOpenSolaris 2009.06 Storage server
3xLSI 3081ER
20xSATA 2.5" RAID10
2xSATA spare
2xIntel X-25M RAID1

Opensolaris hybrid storage pool of harddisks and flash reducing latency
# zpool pool create rr mirror c1t1d0 c1t2d0 log mirror c1t3d0s0 c1t4d0s0 \
cache c1t3d0s1 c1t4d0s1
jumbo frames
zfs set compression=on

Above give you 500MB/s writes and about 1GB/s reads, latency < 5ms turn 
compression on throughput roughly doubles.

//Christian 
_______________________________________________________________
  Christian Nygaard, Sysadmin    Room:   1:4204
  Department of Mathematics,     Phone:  +46  (0)18 - 471 32 37
  Uppsala University.	        Mobile: +46 (0)704 - 25 03 15
===============================================================

On Mon, 10 Aug 2009, Peter Åstrand wrote:

>
> Hi, see comments inline.
>
>>  Actually, I´ve made some calculations based on user´s memory usage on a
>>  real
>>  server (at UERJ) running GNOME 2.26, Firefox 3.0 and OpenOffice 2.4, and
>>  than I  realized that each user consumes from 250 to 350MB of RAM
>>  (consolidating all processes resident set size, RSS), exactly like you
> ...
>>  I could see that GNOME is the great villain here, since it starts a lot of
>
> Yes, this is quite much. It's a little bit funny, because the other day I was 
> talking to a person which claimed that his GNOME desktops only consumed 74 
> MiB per user, considerably less than our estimation of 100-150MiB.
>
> If you consider VDI installations, especially with Windows Vista or 7, then 1 
> or 2 GiB per concurrent user is more typical.
>
> It's clear that there is no such thing as a "standard" desktop; your mileage 
> may vary...
>
>
>>  3) Makes ThinLinc server´s "smarter", to avoid high-memory consumption:
>>  The
>>  idea here is simple, I want to avoid creating more sessions than the
>>  server
>>  can handle. I had some ideas that I would like to share with you. For
>>  example, perhaps if we, based on the user´s pre-defined memory consumption
>>  (like 250MB per user), define that the server could handle 15 sessions, we
>>  could create a way to count down how many sessions are already opened and
>>  deny opening new sessions according to the pre-defined "max-sessions"
>>  limit...
>
> This is an interesting idea. We can consider this for future versions. It 
> should also be possible to create a simple script that simply stops the 
> "vsmagent" service if the load is considered too high (and restarts if when 
> the load is lighter).
>
>
>
>>  Please let me know if any of my ideas makes sense for you, or even if you
>>  are already making efforts on this area acually.
>
> Well, not really, I guess it matters where you live in the world, but here in 
> Sweden, I don't consider the memory prices very high. For example, if you 
> purchase a Dell R710 server, you can upgrade the RAM from 4 GiB to 12 GiB for 
> only ~$300. Assuming GNOME sessions of 300 MiB each, this corresponds to 40 
> sessions, or $7.5 per concurrent user. This is much less than the costs 
> associated with software licenses. For example, the ThinLinc subscription 
> currently costs $75 per concurrent user.
>
>
> Best regards, ---
> Peter Åstrand		ThinLinc Chief Developer
> Cendio AB		http://www.cendio.com
> Wallenbergs gata 4
> 583 30 Linköping	Phone: +46-13-21 46 00
>