Study Notes

A Linux command line: find -name ‘file_name’. its purpose is to find out specific file usring file_name string. I think this command does not do better than “locate” which is more convenient for type.

HPC Benchmarking. The sales are always asked for Benchmarking of the product by the customers in whose mind Benchmarking indicates the performance would help them to select from so many products. In the Lab, we will tuning the system’s structure, for example, If we have four processors(CPU), there are three strategy of distribution. One schema is 4 processors are all on one node, if each node has one processor is also included in the strategy, and perhaps for the best performance, we put two cpus in two machines so that each node has two processors. finally we can determine which hardware to purchase.

What can be done to improve the Benchmark?
—— Modify the data.
—— Tune the application, such as better complier, better libraries, and modify the benchmark code itself.(There are many libraries in the market now, netlib.org and GOTO are opensource, but MPC from Intel must be purchased for business license.However, the former two lib do not supply unbreakable support as Intel’s MPC)
—— Change the hardware.(As we all know, the best rate of EtherNet will be 50-60%,and the InfiniBand will get about 70%). If more money is costed on nodes, less money is costed on communicating hardware, for example, switch, copper line of EtherNet. On the contract, more money is costed on hardware, less money is costed on nodes).

In the Intel trainning camp. HPLinpack is used to indicate Benchmark. Before HPLinpack test start, the Hyper-threading must be off because Hyper-threading technology confused the HPLinpack software.

To tuning performance, the litter value could be ignored or not is usually important to improve performance. we should test and test to find the right answer.

Cluster management tools packages include Portable Batch System(PBS),LSF and SGE. PBS and SGE is open-souce. LSF comes from Canada. In the traing lessons, we put attention on SGE, Sun Grid Engine. which originally developed by Gridware, a company departed from SUN.
We could see the masters and nodes’ statues in the Web brower(Moziila). There is not direct iron in ROCK linux, we run the moziila through click “run applications” and input the localhost IP address. Then three nodes’ details are all displayed in the Web Page writen by PHP.
In the items listed in the former web page, Ganglia is contained because it is installed by ROCKs automatically. Ganglia is used to monitor the cluster in GUI environment.

Before I came here, I was confused about this subject.
Having listened to your lecture, I am still confused, but on a higher level.

——Enrico Fermi

What’s HPC(High Performance Computing)? HPC is based on concurrency that computing in which multiple tasks are active at the same time, and will be used in solving bigger problems or fixed-size problem in less time. For example, scientific computing in physical, biologic or chamical subjects which both have may data need to be access and computed, we could not waiting very long for the computers completed this work. It seems that HPC would solve this problem perfectly.Althought adding more cpus would speed up, but the whole cost become very expensive. The nodes of HPC was common so that all the hardware of the nodes could be brought in the market.In this way, we get better performance with less money.What’s cluster? Collection of connectors, independent computers which work together to solve a problem. When we talk about clusters, the stack including environment (such as location, power,cooling ,sercurity )and assistance (Trainning) must be considered.There are many cluster solution stacks for Linux. OSCAR, NPACI-ROCKS and Score are open-source software, and Scyld and Callident must be purchased for license.

Cluster hardware desire:Interconnect, 100Mps Ethernet, 1Gbit/s Ethernet, SCI, Myricon Myrinet,InfiniBand,Quadrics QsNet(Pay attention to InfiniBand who has another name “IB”). Processors(CPU), all Inter serie processor including P4, Xeon ,Itanium would be used in the Cluster, however, Intel recommends Xeon and Itanium(Tiger 2 Platform). Pentium processor only support 1-way platform, they will cause net constructure more complex.

For example, painting a picket fence, more people can finish painting soon, but all the processing time also including prepairing(loading data) and cleaning up(consume the data) time, we should buy the painter, and clear workspace when the work completed. All of this need time which could not be ignored!So the speedup has a limit pointe when the load and consume time are zero.It is not realizable.
indicate that we could not improve speed only be adding painers. The right way we should found is deciding good price/performaning value.

Load Balancing, when the opera was going to end, some fat woman came out to sing. The load balancing are determined by the slowest nodes because only after this nodes finished working the whole cluster is considered having completed working.Load Balanceing Granularity, when Application granularity matches hardware granularity the cluster gets the best price/performance situation.

Some useful Linux commands:

#server network restart   (when edit the network configuration)
#vi /etc/sysconfig/network-script/ifeth0      (configure the eth0) 
#halt -p  (shutdown the system with power off)
(mount DVD ROM, Linux recognise the DVD as SCSI device)
#mknod /dev/sr0 b 11 0  
#mount  /dev/sr0 /mnt/cdrom

How to install Rocks?
First, insert Rock based CD, and press “f” when displays Rock’s installation logo. In the command line, input “frontend”, then, the Rock will be in setup statues. It will ask for ROLLS which is package of packages in the fact. We input the following three CDs in this sequence “”BASE,HPC,Kernel,SGE”. the installation program runs automaticlly after loading the ROLLS needed. This is called master node.In the second machine named node1, we insert the BASE cd in the DVD ROM, and it will install automaticlly without any user’s action. When installing, the statue list in the master node will display node1.If we have no BASE CD, how could we do to install another node named node2? OK, power on the node2, and press F12 when bios posts. It will come in the PXE starup instance. As same as node2, the installation program runs automaticlly. We need to do nothing so we should drink a cup of water or have a short rest.It is convenience for building the nodes in fast way.

In the morning, Mr King gave us training about memory including DDR and DDR2.

The differences between DDR and DDR2 is DDR2 run faster and has lower working voltage. Some type memory named Rambus, assumed by Intel in 2001, encapsulated in another way.Though Rambus failed in Chinese market in the past three years, many experts thought it will be useful in the future computer systems.

Samsung, Hyrix are the first line manufactor which have good reputation, their products sells very well. In fact, all memery are product in the same working line, however, just like the CPU, they are tested and given a mark as 400Mhz if it is very good, or 333Mhz if it is just OK, and so on.

Registy Memory has register chipset on the PCB which maybe 6 layers or 4 layers. The register chipset buffers the data put in the memory so that Memory will work more stable if a large number of memory would have been requested.

Linux is the best suitable operating system for oracle, only the following OS was certificated by Oracle:

Red Hat Enterprise Linux 4 (RHEL 4), RHEL 3, RHEL 2.1,

Novell SUSE Linux Enterprise Server 9(SLES 9), SLES 8

if recomplie the kernel or use the third-party tools to modify the kernel, Oracle does not supply the unbreakable support. Oracle said there are so many Linux distribution all around the world, it is impossible to certificated every Linux distributions.

As we all know, Tencent Co. used Slackware Linux, which type of database would be instaledl in their servers? DB2, or Sysbase?

I’ve never seen IBM server with AIX through I heard many people said IBM machine was huge and stable.

Load Balancing test, there are totally seven servers as node. 192.168.1.231 acted as the load balancing server,and the others are really workstations whose ip is from 192.168.1.232 to 192.168.1.237.

238 was the loading server which supply the testing pressure.

First, install MS SQL server 2000 in every realy workstations, and let the sql server startup when completed installation.

The engineer from Nanning decided the strategy of cluster and send commands to our server(231) thought moderm which called remote control. About 40 squel instants was started to connect virtual database (192.168.1.231).

In the 231 machine, I could see the statue about connecing and re-connecting,192.168.1.231 is always the server node,and it distributed the load to the other node such as 192.168.1.232 and/or 192.168.1.233.

There are many strategy in the software which is sent to test in the lab. One strategy is that the PC or customer workstation will always connect to the specific node once it was firstly distributed to the node by the 192.168.1.231. Because some people may do some working in one of the nodes, when the node halted, the data the user are working were not committed, so it perhapes lost. we could not imagine what would happen if the important data lost. this accident need the strategy that ensure custmer always connect to the specific server.

Another strategy is random. The customer’s connect will be distributed to random node. With the count of connecting adds, the loading will be balancing automaticly.

By the way, how to setting the display parameter to 1024×768 in Linux? Only changing the parameter in the display dialog is not enough. Login as root, in the /etc/X11 direction, edit the X1186config file by using vi, find the line including”800×600″ “640 x480”, and insert “1024×768” in this line. saved the file, and logout.

Everything will be ok when login as root again.

Install Linux without swap partition and root partition?

The answer is yes.

There are some trouble when install marvell in Intel 7520BD2 platform. custom required Red Hat AS 2.1(2.4.9) as the operating system, however, the marvell driver is developed on 2.4.13 kernel. when forced insert drivers, the following messages displayed: must update your system kernel.

After downloaded the drivers from intel website. I user vi tools to modify the program, and changed the kernel from 13 to 9.

Saved and rebooted, but how disapointed I am. the experice failed.

Ok, I’ll try again.

Today, my MSN blog starts up.

It will be a good platform for people who are insterest in Oracle RAC technology.and some stories about myself also will be writen here. I wish it would be my spirit home in the internet.

# startup