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From:Ph.D. Joseph E. Sacco Date:July 29 2004 3:34pm
Subject:Building a cluster with a slow and a fast machine...
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Systems:
* PowerMac with dual   G4 533MHz CPU's, 1GB RAM, SCSI drives
* Powermac with single G3 240MHz CPU, 264MB RAM, SCSI drives
* Yellow Dog Linux-3.0.1 [Redhat clone]
* mysql-4.1 from BK tree 28July04

====================================================================
Question:

What can be done to improve cluster startup when clustering two machines
with drastically different resource/performance characteristics?

====================================================================

I am running a two replica, four node cluster on two PowerMacs. One
machine is considerably faster than the other:

[Slow G3 machine]
# cat /proc/cpuinfo
processor       : 0
cpu             : 740/750
revision        : 2.2 (pvr 0008 0202)
bogomips        : 478.41
machine         : PowerMac,NuBus
motherboard     : PDM MacRISC
detected as     : 0 (<NULL>)
pmac flags      : 00000000
memory          : 264MB
pmac-generation : NuBus


[Fast G4 machine]
# cat /proc/cpuinfo
processor       : 0
cpu             : 7410, altivec supported
temperature     : 58-60 C (uncalibrated)
clock           : 533MHz
revision        : 17.3 (pvr 800c 1103)
bogomips        : 1064.96
 
processor       : 1
cpu             : 7410, altivec supported
temperature     : 34-36 C (uncalibrated)
clock           : 533MHz
revision        : 17.3 (pvr 800c 1103)
bogomips        : 1064.96
 
total bogomips  : 2129.92
machine         : PowerMac3,4
motherboard     : PowerMac3,4 MacRISC2 MacRISC Power Macintosh
board revision  : 00000000
detected as     : 69 (PowerMac G4 Silver)
pmac flags      : 00000000
L2 cache        : 1024K unified
memory          : 1024MB
pmac-generation : NewWorld

It is often difficult to get the DB nodes on the slower machine to
start. It typically takes several attempts to get the two nodes on the
slow machine up and running. Once the cluster is established it is
stable.

One of the things I have noticed is the DB node startup process on the
slow machine temporarily spawns a *large* number of ndbd processes.
During the startup it is not uncommon to see 20 -> 30 ndbd processes
started, which effectively overload the slow machine. Once all the nodes
in the cluster are up and running the number of ndbd processes drops to
two per DB node.  

What's going on??? Are things timing out so the "Angel" processes
continually fire up other ndbd processes?  If so, what can be done?

-Joseph


-- 
Joseph E. Sacco, Ph.D. <jsacco[at]earthlink[dot]net>

Thread
Building a cluster with a slow and a fast machine...Ph.D. Joseph E. Sacco29 Jul
  • Re: Building a cluster with a slow and a fast machine...Magnus Svensson3 Aug
    • Re: Building a cluster with a slow and a fast machine...Ph.D. Joseph E. Sacco3 Aug