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On Tue, 3 Jul 2007, Rio wrote:
>> You have one box which is running 84 instances of a virtual
>> server and another box which has 40 instances. So you have
>> two boxes which can appear to be 124 realservers?
>>
>
> to the outside world (not admins) the 124 virtual servers appear to be
> individual discreet servers. i think i may be confused by the term
> realservers.
realserver is an LVS term referring to the machine/node(s)
that are being loadbalanced by the director.
I've never liked the LVS nomenclature; e.g. "virtual",
"realserver", but since I couldn't come up with an
alternative and no-one else seemed to mind, I've just
accepted it. We haven't had too much problems with the word
"virtual" since we haven't run into other projects using the
term much. However if realservers are going to be
virtualised, there's going to be lots of name space
collisions.
>> so you have 84 virtual machines but they don't appear to be
>> 84 individual machines?
>>
>
> i was comparing the context oriented virtual servers using
> a single master kernel on the host to 'virtual machines'
> such as that presented by vmware with their own virtual
> hardware requiring complete o/s installs with kernels,
> modules etc.
Gerry has straightened me out here.
>> what are "context virtuals" (nothing useful found in
>> google).
>
> bad description :) each of our virtual servers runs in its
> own 'context' (unique number). i think the description
> from the linux-vserver website says it much better than i
> possibly could:
OK, better go look these up. Better go look at the OpenVZ
project docs too.
> 2 of them plus the new one to be added are tyan gx28
> servers with 2 dual core opteron processors giving it 4
> cores, 16gb ram. one server has no need for more than 2
> nics so the 3 on-board are sufficient, but the other one
> uses the 3 built in nics plus a 4 nic card. this serves 5
> discreet networks in addition to our pvtnet and our own
> public net. when we change over to mirroring/lvs control
> we will add nics to make all 3 servers identical.
The hardware then is a 4 core box. Since the dual core
opterons don't have any more memory bandwidth than the
single core CPUs, you can only use both cores at the same
time if one core is running its application in L1/L2 cache.
I don't know what service you're planning on balancing, but
since most people use LVS for loadbalancing http, let's talk
about http. (since http is just fetching pages from disk
cached in RAM, I don't expect you'll get much for your two
cores). My original question then is (using Gerry's
nomenclature)
o How many httpd realservers would you choose to run as VEs
on this box and why do you choose that number? ie why don't
you run just one VE realserver?
Joe
--
Joseph Mack NA3T EME(B,D), FM05lw North Carolina
jmack (at) wm7d (dot) net - azimuthal equidistant map
generator at http://www.wm7d.net/azproj.shtml
Homepage http://www.austintek.com/ It's GNU/Linux!
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