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Constrained vs UnConstrained

Created: 18 Oct 2009 • Updated: 19 Jun 2014 | 3 comments

To all you guru's out there...This a bit of an off the wall question, but it appears not to be clarified anywhere. Situation is like this:

Normally the process of constraining packages servers has a two fold purpose, a) to reduce the load on the NS, and b) to reduce bandwidth usage over WAN links in situations where a 2nd and 3rd tier network structure exists. This process is alse normally implemented along with manual site additions such that the 2nd tier package server would be added to the 3rd tier site. Doing this then with the 3rd tier constrained, the 3rd tier package server will download from the 2nd tier package server only. after that mouthful...there exists a twofold issue with the process of constraining. Firstly, it cannot be effectively implemented in a multi-tiered environment since a constrained package server cannot download from another constrained package server. The 2nd issue is that there seems to be an issue with numbers such that no more than 99 sites may be attached to a single package server... (don't know why this is, it just messes everything up if you try it)

So then, if we leave the constraining bit out of it, but still want to save on the bandwidth side of things we could try to still do the association of the different nearby sites...problem is though, the NS will then assign that site (and it associated pkgsvr) to be the source for download...the possibility of then going into a loop situation where the site on the other side of a very small link get's to be the download source for it's upsream mate which incidentially has much greater bandwidth back to the NS (but is just much further away) is quite likely...the result is therefore that the delay in getting the packages to the second tier becomes serously lengthened.

What to do? The notion of constraining every server except the pkgsvrs at the HQ location where the NS is based has occurred to me, but, I don't know whether it may be done without the site association part of the process mentioned above... in other words... IF I constrain WAN tier 1, 2, and 3, make no associations in terms of sites, will the NS automatically assign the best responding unconstrained pkgsvr to service the request? IN this instance that unconstrained pkgsvr would be the ones based at the HQ (same LAN as NS).

I know this would not save bandwidth, but it will reduce the load on the NS.

Any comments?

many thanks

Comments 3 CommentsJump to latest comment

naugello's picture

Agreed on the 3 tier issue with constrained package servers.   We attempted NS -> High speed site Package Server -> Low speed site package server. This was accomplished by creating a site that  for the low speed site and added manually assigning the High Speed package server to that site.  This worked as long as the  package server agent on low speed site was working properly and downloading all the available packages.

We ran into issues where the Altiris Agent/ package server agent would not download all the packages until the service was restarted, The clients at the slow speed site would attempted to download from it's local package server but when it did not have the package it attempted to get it over the slow wan link from the high speed site.

This led me to removing the high speed package server from the low speed "site" removing the 2nd tier from the hierarchy.

jloubser's picture

After much deliberation and investigation I have come to this conclusion concerning the above topic:

The merits concerning the application of constraining specific package servers (now referred to as site servers) is only useful in 2 instances:

a) The servers you wish to constrain have other servers from which to pull (synchronise) in the same PHYSICAL site (i.e. LAN connected)
b) In the event that no additional server exist in the same physical site, the servers you wish to constrain are connected via high speed links (i.e. T1 plus) to other Physical sites and that such servers at these remote high speed connected sites are then placed into the same Logical site as the former now constrained server.

Other than this there is no merit in constraining servers at all. It cannot be used to conserve bandwidth in a WAN type scenario where the desire to save bandwidth arises because of small bandwidth issues and a thrid tier is in existance.

I welcome anyone who has a view differing to this to comment.


jharings's picture

However, Jacques, I believe you are right on target. I will add that I personally have seen few configurations with multiple package servers in the same site, at least for the initial implementations.

Jim Harings
HP Enterprise Services
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