XGE

Timestamp:

04/13/08 10:13:41 (5 years ago)

Author:

MatthiasSchmidt

Comment:

Add details about deployment algo

Design

@@ -20 +20 @@
 The time needed to deploy the VM images to a number of nodes is crucial.  If it takes to long a user could assume a possible error and cancel his/her job not knowing that a lengthy deployment process is in progress. Furthermore deploying a large number of VM images over a network consumes a lot of bandwith and could lead to network congestion.  Image if a 5 GB VM image gets copied from one machine to 1000 remote machines. All copy processes have to share the bandwith between the source machine and the connected switch port.
 
-The above stated problems need clever algorithms to deploy the VM image to a large number of nodes without exhausting the infrastructure. The algorithm used by default is a binary tree deployment algorithm. 
+The above stated problems need clever algorithms to deploy the VM image to a large number of nodes without exhausting the infrastructure. The algorithm used by default is a binary tree deployment algorithm. The VM image is copied from the Image Pool to the first node, if we have an odd number of compute nodes for this job.  If we have an even number of compute nodes the VM image is also copied to the "last" compute node.  If a reasonable number of bytes arrive at the first node, the VM image is copied in parallel to both children nodes. This recursive procedure ensures that the VM image arrives on all compute nodes without exhausting the network. Furthermore there is a reasonable time gain over serial copying. A schematic overview over the binary tree is given in the following figure:
 
-XXX mehr hier
+[[Image(xge_bin_tree.png)]]
+
 
 == Placeholders and Real Virtual Machines ==