Problem Determination Guide - Systems Group

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1.5 Front-End Node A Front-End Node is another IBM System p running SUSE Linux Enterprise Server 9 (SLES 9). Multiple Front-End Nodes can be installed. This is where the users log into and submit jobs to the Blue Gene/L. IBM compilers and Blue Gene/L compiler extensions are installed so that the user can cross compile code so it will run on the Blue Gene/L hardware. The user then submits the job to the system through a job scheduler. The Front-End Node is needed because compilations and handling job I/O from many users can have a severe effect on the performance of the Service Node. You can find more information about compiling and submitting jobs in Chapter 4, “Running jobs” on page 141. 1.6 External file systems As we explained in 1.3.2, “Functional network” on page 24, the Blue Gene/L system does not have any persistent storage (disk) directly attached. Storage is provided through external file systems such as NFS or GPFS (as illustrated in Figure 1-28). These file systems are then mounted by the I/O nodes, and the Compute nodes perform I/O through the collective network. You can find more information in Chapter 5, “File systems” on page 211. 32 IBM System Blue Gene Solution: Problem Determination Guide
Front End Node Job Job Scheduler ciodb idoproxy mmcs_server DB2 Service Node Figure 1-28 Communication in Blue Gene/L 1.7 Blue Gene/L system software 1.7.1 I/O node kernel NFS/GPFS Functional Network Service Network CIOD Blue Gene/L I/O Node(s) Compute Resources iDo to JTAG Block So far we have talked about the physical hardware and software that runs on the Service Node. Now, we move onto the software that actually runs on the Blue Gene/L hardware (compute and I/O nodes). When a block is booted, each I/O node within that block receives the same boot image and configuration. This is in fact a port of Linux with specific patches to support the Blue Gene/L hardware. This altered kernel is also known as the Mini-Control Program (MCP). It is seen as linuximg in the block definition and has a small specialized shell that provides a subset of commands and command options called BusyBox. The I/O node boot scripts run the BusyBox commands. Chapter 1. Introduction 33
Page 1: IBM System Blue Gene Solution Probl
Page 4 and 5: Note: Before using this information
Page 6 and 7: 1.7.5 Microloader . . . . . . . . .
Page 8 and 9: 4.4.2 Principles of operation in a
Page 10 and 11: Installing LoadLeveler on SN and FE
Page 12 and 13: Trademarks The following terms are
Page 14 and 15: He holds a Master's Degree in Elect
Page 16 and 17: Frank Ingram Randal Massot Mike Nel
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Page 20 and 21: 1.1 Blue Gene/L system overview In
Page 22 and 23: Figure 1-2 Card positions in the fr
Page 24 and 25: 1.2.2 Midplane As the name suggests
Page 26 and 27: 1.2.5 Node card As an application r
Page 28 and 29: Figure 1-8 Node card center LED pan
Page 30 and 31: Status LEDs are located on the righ
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Page 34 and 35: The BPMs also have status LEDs, as
Page 36 and 37: Figure 1-17 Link card that shows th
Page 38 and 39: Fan assemblies: Rxx-Mx-Ax Fan assem
Page 40 and 41: 1.3.1 Service network The service n
Page 42 and 43: I²C The Inter-Integrated Circuit (
Page 44 and 45: 1.3.3 Three dimensional torus (3D t
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Page 48 and 49: ► Configuration data: Includes sy
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Page 56 and 57: After the chips are initialized, th
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Page 60 and 61: Frontend Node Job Job Scheduler mpi
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Page 70 and 71: EndServiceAction logs its invocatio
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Page 74 and 75: 2.1 Introduction Whenever you have
Page 76 and 77: The Configuration section displays
Page 78 and 79: 1 record(s) selected. Then check th
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Page 82 and 83: Table 2-6 Control system log for pe
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Page 86 and 87: 2.2.10 Midplanes 2.2.11 Clock cards
Page 88 and 89: 2.2.13 Link cards ► Using a DB2 s
Page 90 and 91: Figure 2-6 BGWEB table showing the
Page 92 and 93: 2.2.15 Link summary You can view th
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To check the number of processor ca
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etc/shadow:bglsysdb:$1$SwI1..4e$iGN
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4. Use the /bin/ping command to che
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If you discover issues during the c
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2. If you need to restart BGLMaster
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2. After you are connected to the c
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Apr 05 17:20:57 (I) [1090516192] te
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2.3.8 Check that a simple job can r
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Figure 2-16 BGWEB showing job Infor
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To check the control system server
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If there is an issue with rsh, then
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2.3.13 Check the physical Blue Gene
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This methodology also allows someon
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- Hardware 3.2, “Hardware monitor
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BRIDGE (Debug): rm_add_job() - Comp
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112 IBM System Blue Gene Solution:
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3.1 Introduction This chapter expla
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Using the GUI If you have a graphic
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Figure 3-2 Querying the environment
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3.3.1 Starting the tool Figure 3-4
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Figure 3-5 Missing hardware in a re
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Block information The block informa
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In addition, the Show RAS events fo
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Figure 3-11 RAS drill down showing
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Figure 3-14 Testcase highlighting t
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3.4.1 Test cases The diagnostics su
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3.4.2 Starting the tool Test case D
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While the Web interface provides a
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Apr 06 18:59:41 (I) [1079031008] {1
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4.1 Parallel programming environmen
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4.2 Compilers The following steps e
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Because these RPMs can be downloade
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4.2.2 The IBM XLC/XLF compilers Thi
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of providing this access for the ad
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The system administrator can set up
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Note: A similar configuration is pe
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► DB_PROPERTY This setting is def
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BRIDGE (Info) : The machine serial
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In Figure 4-3, clicking Runtime dis
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The Web page shown in Figure 4-4 al
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Figure 4-5 shows a diagram of the j
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Users and system administrators can
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A node part of a LoadLeveler cluste
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4.4.2 Principles of operation in a
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Start daemon (startd) runs on each
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The binaries are located in /bgl/Bl
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Because these variable are user spe
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4.4.8 LoadLeveler job submission pr
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Figure 4-14 shows the process of Lo
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Steps 5 and 6: Initializing the par
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Steps 8 and 9: Starting the paralle
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Service Node Central Manager Figure
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4. One of the start daemons is down
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Z = 0 ===== +------------+ | R000|
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Z = 0 ===== +----------------------
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You can use the llq -l command to
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Submitting Host: bglfen1.itso.ibm.c
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Note: The JOBID from Blue Gene/L da
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► #@ arguments This keyword conta
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LoadLeveler processes, logs, and pe
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You can configure the LoadLeveler d
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► STARTD_RUNS_HERE This keyword s
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For example, knowing how sockets wo
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5.1 NFS and GPFS In a basic configu
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sshd (optional) Starts the secure s
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1. Create NFS Server with storage a
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5.2.4 NFS checklists the simplest p
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Step 2 - Check if the NFS-FS can be
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# It mounts a filesystem on /scratc
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5.3 GPFS Example 5-6 Recommended ne
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However, if you have the following
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nodes and these have no boot/OS dis
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Important: The GPFS code that is in
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5.3.6 Creating the GPFS file system
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Installing the GPFS code for SN Fig
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You should see a list similar to th
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172.30.1.1 bglsn_fn OpenPower Servi
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Having created the /tmp/authorized_
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When the "GPFS_STARTUP=1" line is i
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Creating the bgIO cluster After you
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Mon Mar 20 14:14:34 2006: mmfsd rea
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Example 5-21 Telling clusters to au
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To mount the GPFS file system on th
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Example 5-25 Node definition file f
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5.3.9 GPFS problem determination me
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Checking the GPFS log files for pro
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Node number Node name GPFS state --
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Example 5-35 shows the output of th
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We also ran the mmlscluster command
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5.3.11 References For more informat
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6.1 Introduction In some scenarios,
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6.2.1 Hardware error: Compute card
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Example 6-2 mmcs message: service c
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Problem determination When we boote
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Looking in the system logs we see t
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Lessons learned The /tmp directory
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Mar 14 12:27:04 (I) [1079567584] Ab
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Lessons learned We learned the foll
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glsn:/bgl/BlueLight/ppcfloor/bglsys
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6.2.12 DB2 not started on the SN In
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Now we start DB2 on the SN; after D
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After changing the db.properties wi
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Mar 15 17:04:33 (I) [1086321888] ro
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Current message level: 0x00000007 (
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As EndServiceAction did not complet
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Mar 13 16:02:17 (I) [1084843232] ro
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Problem determination In this scena
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** error ** ** error ** ** error **
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Mar 28 15:56:48 (I) [1088451808] ro
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-rw-r--r-- 1 root root 220 Mar 19 1
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Summary: api = MPIIO (version=2, su
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Are you sure you want to continue c
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Now that we know that the GPFS conf
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Lessons learned From this scenario,
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We can see that the partition is st
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Ckpt Execute Dir: Restart From Ckpt
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We realize that we cannot find eith
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Note: Even though we can manually c
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-rw-r--r-- 1 root root 58882 Mar 31
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Step 1 Now we install the new Blue
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We used the updated script to retri
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Example 6-66 shows the files that w
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The BACKFILL scheduler with Blue Ge
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Log will be written to /bgl/BlueLig
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However, we were able to ssh to the
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8. We try to run a job. We start by
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Summary: api = MPIIO (version=2, su
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11.We test that we can boot a block
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delaying 1 seconds . . . write 6.61
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clients = 128 (16 per node) repetit
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Problem determination When we ran t
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7 ionode6 active 8 ionode7 active 9
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6.4.2 The mpirun command: environme
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BE_MPI (Info) : == BE completed ==
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Problem determination By default, t
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# bglfen1 test1 bglfen2 test1 bglsn
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6.4.4 LoadLeveler: scenarios descri
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FE_MPI (Info) : Scheduler interface
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The log messages indicate the job c
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Problem description A job submitted
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MAX_JOB_REJECT = 0 # # When ACTION_
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From the StartLog, we can see that
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Detailed checking We start by check
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Example 6-121 LoadLeveler basic che
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We first check the LoadLeveler Nego
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The error messages shown in Example
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04/05 15:30:28 TI-6 LoadLeveler: Ba
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To detect the left-over socket file
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7.1 Cluster Systems Management This
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7.1.2 Monitoring the Blue Gene/L da
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To simplify the earlier monitoring
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Description = This sensor is update
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To verify that all is working prope
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7.1.5 Miscellaneous related informa
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The cryptographic technique are emp
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► RC2/RC4 algorithms RC2: block c
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Secure shell server The secure shel
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Secure shell client programs also d
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► If this file exists, it checks
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► We restarted the ssh daemons on
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Installing LoadLeveler on SN and FE
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Create the home directory for user
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Example A-3 presents a sample LoadL
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Example A-4 presents a sample LoadL
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CKPT_CLEANUP_INTERVAL = 86400 # sam
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# STARTER = $(BIN)/LoadL_starter ST
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# MAX_JOB_REJECT = 0 # # When ACTIO
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The /bgl/dist/etc/rc.d/init.d/sitef
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# ---------------------------------
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# Parameter 1: "start" - perform st
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gl/BlueLight/ppcfloor/docs/ionode.R
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------------------------------- The
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BGL_BLOCKID Name of block BGL_VERBO
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to by Normally, you should not have
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] to by 440 IBM System Blue Gene So
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GPFS_VAR_DIR directory. GPFS_CONFIG
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$BGL_SITEDISTDIR/etc/rc.d/rc3.d dir
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# Handle startup (start) and shutdo
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Support for Subnets ---------------
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mv ramdisk.img2.gz ramdisk.img.gz L
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RSH Remote Shell SHA Secure Hash Al
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Online resources These Web sites an
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clock signal 11 cluster 168 Cluster
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mmauth 247-248, 261 mmchconfig 247,
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XL compilers 148 XLC/XLF 148 XLC/XL
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IBM System Blue Gene Solution Probl
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