Status of the new NA60 “cluster”

Objectives, implementation and utilization

NA60 weekly meetings

Pedro Martins

03/03/2005

Why do we need another PC farm?

I. Several monitoring/DAQ PCs used during the 2004 Proton Run are now switched off, waiting for the next run in 2006 (at least). It’s a waste of money.

II.Our “offliners” already asked for more computing power. With two farms, we always have one “backup” system. We have plenty of data from 2003 and 2004 to analyse and all the help we can get is welcome.

Technical Objectives

The user should see only one machine, like in a supercomputer.

The maintainance should be kept to a minimum.

The system should be flexible, able to easily add and remove nodes (PCs).

OpenMosix

Gentoo

Remote boot, diskless support

Openmosix

•Easy implementation,•Node discovery tool,•Migration of processes

A single process, like a macro, is NOT going to be shared among all computers. Each process goes to one CPU only.

In principle we can run as many processes as the number of CPUs we have.

Gentoo

•The Scientific Linux does not allow (to the non-IT user) the creation of clusters,•Simple maintenance, using Portage.

CERN/IT does not support Gentoo based OS. Our IT experts will be the only ones solving the problems.

Advantage?

The previous data from the machines is kept, meaning that we always have a fallback option.

Remote boot, diskless support

Na60pc08 is our cluster's disk server:•It provides network information to all nodes,•controls the process migration,•makes the interface with the user.

na60pc08

Node 1 (diskless)

Node 10 (OS on local disk)

NAT

•Boot and network information,•OS data.

•Network information

CASTOR, na60tera1, na60tera2...

nfs

OpenMosix migratorvncssh

user

Present status

• The main node (na60pc08) is operational. • One node with local disk is fully working.• Another diskless node is still in the debug

phase.• Our “cluster” is still small but it has

already a considerable power (P4 2.4GHz, AMD 1GHz and 1.5 GB RAM).

• Since the Memory Migration feature doesn't deal properly with the X server, we are using VNC. Actually, VNC is much better than an X remote server, since it compresses the data transferred through the network, allows remote connections from windows and linux machines and is acessible from outside CERN (IT allows this).

To do list

Queuing (FIFO) tool, like auson:– It will use the “cpujob” and “iojob” commands that send the

processes to the adequate nodes,

Debug the diskless implementation, checking with a new diskless machine,

Connect as many machines as we can.

Write a Howto/FAQ for the offliners.