Local Grid Bonding

General DPM performance issues

The data that can be read/written from a disk pool node is limited by several factors:

• the speed that data can be read/written from DPM disk areas. This is limited by the method of connection of the disk devices, which in our case is via dual SCSI each at 320 MBytes/sec.
• the speed that data can pass through the network between client and server. This is affected by number and speed of network interfaces, and the network switch setup.
• in both these aspects, there is contention between the different clients accessing the SE or pool nodes simultaneously. Each receive a share of the available bandwidth. This favours a setup where there are multiple disk pool nodes, either each exclusively handling a reasonably small quantity of data, or each able to have uncontended access to all the storage.
• There is also contention within a worker node, between the different clients (eg rfcp) on the same node. These share the same WN network interface(s).

Implementing network bonding

I've implemented network bonding on the disk pool node epgsr1, in order to help with a bottleneck which became clear during the running of STEP 09.

Switch Setup

Pool node Setup

-- LawrenceLowe - 11 Jun 2009