[Date Prev][Date Next] [Thread Prev][Thread Next] [Date Index] [Thread Index]

Re: linux friendly hardware inquiry/advise

On 10/19/2011 11:28 AM, Camaleón wrote:
> On Wed, 19 Oct 2011 22:24:37 +1000, yudi v wrote:
>> Building a new PC, will be used for coding mostly, running 2-3 VMs
>> simultaneously.
> Then -although you have not say any specific number- add more ram (8 up 
> to 24 GiB is a good starting point) ;-P

8-24GB?  For a development box running 2-3 VMs?  That's overkill.  Let
me explain.

At a previous $day_job a few years back we were running a mix of 13 SLES
9/10, W2K3, and Sarge VM guests across two dual CPU dual core Opteron
2GHz IBM blades (4 cores/blade) with VMware ESX3.  Each blade had "only"
8GB RAM.  Additionally, were were running the 32 bit VMware kernel with
PAE as the native 64bit kernel wasn't available yet.  All the VMs were
32bit as well.

These were all production server VMs and many had decent load all day
long.  This included our MSSQL server, two MS AD DCs, a print server, a
file server, Novell iFolder server (heavy load), two DHCP servers, a Zen
server for imaging laptops (heavy load), two intranet web servers, and
the Sarge VM serving NTP, etc, etc, all to ~500 laptop and desktop
clients.  Even without using the memory consolidation feature of ESX, we
were able to vmotion all the guests to one blade allowing us to do
maintenance on the other.  That's 13 Linux and Windows guest VMs on a
single 8GB box, and there was no noticeable decrease in performance on
any application when all the VMs were on one blade with only 8GB RAM.

With or without using KSM
(http://www.kernel.org/doc/Documentation/vm/ksm.txt), Yudi should be
able get by easily with 4GB of RAM. As memory is so cheap these days he
may as well get 8GB.  Anything over that is money wasted, no matter how
little, on simply having more buffer cache.  If we were runing 13 VMs in
8GB, surely he can run 3 in 4GB.


Reply to: