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From:Jim Hoadley Date:February 2 2005 7:23pm
Subject:Re: It's not going well....
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Mikael et al. --

>Actually in multi-CPU boxes it can be very
>beneficial to lock the ndbd process to a CPU (advantegous also from use of
>cache memory and gives very predictable performance) if the OS supports
>such actions.

This brings to mind 2 general questions. 

1) If I am putting together a 3-node cluster (API and NDB on BOX1, API and NDB
on BOX2, MGM on BOX3), how much will it help to buy 2-CPU boxes instead of
single CPUs? Worth the added price? These would be something like 3.6GHz Xeon,
4GB RAM and 2 36GB 10k RPM SCSI drives.

2) If so, what kind of performance gain, if any, would I get from locking the
NDBD process to one of the CPUs?

Thanks in advance!

-- Jim Hoadley


--- Mikael Ronstr
> Hi,
> 
> 2005-02-02 kl. 01.58 skrev Mike Schroeder:
> 
> > I have similar questions:
> >
> > So if we use dual 64-bit AMD Opterons with 16 GB RAM, will MySQL 
> > access all 16 GB?
> > Has anyone found any point of diminishing returns on the amount of 
> > memory in a server?
> > Which is better: fewer servers with more memory, or more servers with 
> > less memory?
> >
> 
> If the OS is 64-bit the answer is yes, both for the MySQL Server and 
> for the ndbd processes
> in the MySQL Cluster. For a 32 bit OS, the limitation on OS exists as 
> Marco W. pointed out
> below. For ndbd processes Marco W. notes were correct that you can run 
> several ndbd processes
> per box to make use of a memory bigger than 4 GB (my experience is that 
> the limit is even 3 GB or
> less since the OS uses up some of the virtual memory addresses plus due 
> to fragmentation of
> virtual memory address space).
> 
> Whether to use fewer servers or more servers is more dependent on the 
> number of CPU's. One ndbd
> can make use of between 1-2 CPU's so if you have a 4-CPU box you need 
> at least two ndbd or one
> ndbd + mysqld to fully utilise the CPU's. It is also a matter of 
> whether best throughput or lowest latency
> is desired. Best throughput is achieved if you allocate around 1 CPU 
> per ndbd node and best latency
> if you have 1.5-2 CPU's allocated to the ndbd process. Actually in 
> multi-CPU boxes it can be very
> beneficial to lock the ndbd process to a CPU (advantegous also from use 
> of cache memory and gives
> very predictable performance) if the OS supports such actions.
> 
> Rgrds Mikael
> 
> >
> >
> >
> >
> > Marco Wertejuk wrote:
> >
> >> Hey,
> >>
> >> | What is the limitation of a 32-bit architecture as it
> >> | relates to RAM and MySQL Cluster?
> >>
> >> I actually don't know about how mysql cluster is programmed
> >> according to memory usage, but I can tell you that no
> >> application can use more than 4GB memory on 32bit x86
> >> servers. Redhat enterprise supports more that 4GB using
> >> high address memory and em64t technology, but due to
> >> how memory configurations above the 32bit address limitations
> >> are supported no application can use more than 4GB.
> >>
> >> Of course you can run 2 4GB memory consuming applications
> >> on you 8GB server but this might not work with mysql cluster.
> >>
> >> You should probably consider using a 4 node cluster where
> >> you have 2 groups with each 2 nodes for redundancy and splitting the 
> >> dataset across two servers.
> >>
> >> I think this will be easier for you at the cost of
> >> more hardware and probably more point of failures.
> >>
> >>
> >
> > -- 
> > MySQL Cluster Mailing List
> > For list archives: http://lists.mysql.com/cluster
> > To unsubscribe:    
> > http://lists.mysql.com/cluster?unsub=1
> >
> >
> Mikael Ronstr> MySQL AB, www.mysql.com
> 
> Jumpstart your cluster:
> http://www.mysql.com/consulting/packaged/cluster.html
> 
> 
> --
> MySQL Cluster Mailing List
> For list archives: http://lists.mysql.com/cluster
> To unsubscribe:    http://lists.mysql.com/cluster?unsub=1
> 
> 



		
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Thread
Re: It's not going well....RadeonFlashBox1 Feb
  • Re: It's not going well....Marco Wertejuk2 Feb
    • Re: It's not going well....Mike Schroeder2 Feb
      • Re: It's not going well....Mikael Ronström2 Feb
        • New ...Hasan Subasi2 Feb
        • Re: It's not going well....Jim Hoadley2 Feb
          • Re: It's not going well....Mikael Ronström2 Feb
            • Re: It's not going well....Vincent Bray3 Feb
              • Re: It's not going well....Stewart Smith4 Feb