Trending algorithm for performance monitoring
-- Situation description

I'm trying to implement a prediction (or trending) algorithm for my performance gathering system in order to see when a Linux server's resources will end (for example, free space on a storage or free memory).

The result of the performance gathering process is a graph. So, I need to get on my graph something like this:

<a href="http://imgur.com/GJCyh"><img src="http://i.imgur.com/GJCyh.png" alt="" title="Hosted by imgur.com" /></a>

This is an example of RRDtool graph (data collected from Cacti monitoring tool). 
Here are 3 dashed lines that are trend lines for the disk utilization history graph.
That is similar to what I need.

-- So, what I would like to get:

The prediction of when the performance will reach some value (e.g. 90%).
Which of the plenty of prediction (trending) algorithms should I use in my case?

-- What I've researched:

Holt-Winters algorithm, time series prediction. But I do not know how to use them in this particular case. May be there is other solution?

-- Additional info

[30,45,50,10,20,30] -> this is example of disk utilization array (in %) in time. Data collected every minute.

Critical threshold boundary is 90%.

I need to know when the disk utilization will reach 90% threshold (based on the already collected history of data).

 

 
Trending algorithm for performance monitoring
===

-- Situation description

I'm trying to implement a prediction (or trending) algorithm for my performance gathering system in order to see when a Linux server's resources will end (for example, free space on a storage or free memory).

The result of the performance gathering process is a graph. So, I need to get on my graph something like this:

<a href="http://imgur.com/GJCyh"><img src="http://i.imgur.com/GJCyh.png" alt="" title="Hosted by imgur.com" /></a>

This is an example of RRDtool graph (data collected from Cacti monitoring tool). 
Here are 3 dashed lines that are trend lines for the disk utilization history graph.
That is similar to what I need.

-- So, what I would like to get:

The prediction of when the performance will reach some value (e.g. 90%).
Which of the plenty of prediction (trending) algorithms should I use in my case?

-- What I've researched:

Holt-Winters algorithm, time series prediction. But I do not know how to use them in this particular case. May be there is other solution?

-- Additional info

[30,45,50,10,20,30] -> this is example of disk utilization array (in %) in time. Data collected every minute.

Critical threshold boundary is 90%.

I need to know when the disk utilization will reach 90% threshold (based on the already collected history of data).

 

 