Slave Servers Requirements

This page describes our recomendations to add an slave server to giss network.

It's based on our experience and the actual requirements of the icecast master/slave infrastructure to allow all the mountpoints in use at one time.

Recomendations to add an icecast slave server to relay all mountpoints

This params works in the courrent situation where we have an stable 25/30 sources at the same time in giss, but that sometimes increase to about 40. This params are fine in the situation that 40 stables sources are online with 4 stables clients each one along all the month, what means 200 connections at the same time of about 100 kbps. Perhaps this is not a realistic situation at all but perhaps it's a good start point to measure this question.

Bandwidth: 20 mbps dedicated up/down

Monthly Transfer: 5TB / month

Server Software: as described in Servers Configuration

Server Hardware: 2,4 Ghz CPU / 512 RAM

And to add an icecast slave server to relay only some mountpoints

If you have X bandwidth and you want to join your server to giss, we recomend to tune icecast params like this:

X bandwith in kbps / 100 kbps (aprox for each connection) = max simultaneus connections
1/5 max simultaneus connections = max sources param in icecast conf
4/5 max simultaneus connections = max clients param in icecast conf

If you have monthly transfer limits in your server you should know that one slave with about 25 sources online at the same time and without clients consumes each day about 20GB, or 600GB at month.

This way you can tune params in icecast like this:

X GB monthly transfer allowed / 25 (GB/connection/month) = max simultaneus connections
1/5 max simultaneus connections = max sources param in icecast conf
4/5 max simultaneus connections = max clients param in icecast conf

Well, it's not a science as you can see. The 4 clients for source is an arbitrary number and the 100 kbps for each connection is more than it usually is. Besides, clients are not all the time connected, so this params refers to the ideal situation where the slave server is at 100%, in the proportion of 4 clients by source... As this is not realistic at the moment, you could start with this recomendation and increase values step by step.

For instance, start with a conf of:

bandwidth 20 mbps
monthly transfer 1 TB 
max sources 10 ( double of the recomended using the monthly transfer calculation)
max clients 160 ( the recomended using the bandwidth calculation)

is a good choice.