[OpenAFS] GSoC Server priorities

[Lars Schimmer]

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Jake Thebault-Spieker wrote:
> On Thu, Oct 15, 2009 at 2:19 AM, Lars Schimmer <l.schimmer@cgv.tugraz.a=
t>wrote:
>=20
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>> Hi!
>>
>> I've seen the code for server priorities made in a GSoC is in the
>> private windows test builds.
>>
>> As it could solve one smaller design problem for us, one question is o=
pen:
>> On which base does it rate server "near" and "far"?
>> AFAIK based on RTT time.
>>
>=20
> Current private builds use RTT as taken from the rx statiscs that are
> gathered on a per-client basis, and use a log (base-e) scale to provide=
 a
> rank based on the RTT.
>=20
>=20
>> Our setup is expanded with a fileserver with only RO on a different
>> subnet some miles away, attached to us via a static VPN.
>> In one of our private subnets we drive our CAVE and this subnet is not
>> routed accross the VPN - if we put the CAVE ROs on the fileserver on t=
he
>> far away fileserver, the clients does not reach them.
>> For now, the ROs are not there (kinda bad in kind of backup reasons).
>> Could this new feature solve this (in a bad way, I know) with just rat=
e
>> the "bad" fileserver horrible bad?
>>
>=20
> If I understand what your end goals are, you're trying to minimize the
> amount of traffic to the file server on the other side of the VPN. If t=
his
> is the case, then there is functionality available currently, using "fs
> serverprefs". The administrator can set the server rank much higher tha=
n the
> ranks the other servers are being given, and this server will only be
> interacted with if all the other servers with lower ranks are down.
>=20
> The RTT based ranking only gets taken into account when there are rx
> statistics collected by the client, so if the client has never interact=
ed
> with the file server on the other side of the VPN, there will be no rx
> statistics gathered, and the rank will default to the current scheme (b=
ased
> on which machine, subnet, network the server is on compared to the clie=
nt).
>=20
> I hope this helps, please clarify if I misunderstood your goals. If you=
 do
> try it, I would appreciate feedback you have.


Thank you, that helped.
Our point is: we got some clients in a 10.x subnet which is not routed
across VPN ad therefore those clients cannot reach that fileserver.
An as you tell, based on transmitted rx - with no traffic, no stats, no
change for us.


MfG,
Lars Schimmer
- --
- -------------------------------------------------------------
TU Graz, Institut f=FCr ComputerGraphik & WissensVisualisierung
Tel: +43 316 873-5405       E-Mail: l.schimmer@cgv.tugraz.at
Fax: +43 316 873-5402       PGP-Key-ID: 0x4A9B1723
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