[dba-Tech] VMWare VM and shared RAMDISK

It appears that when I start the second machine it hits the swap file a lot
or something.  These machines are each 2.X gigs of memory and need to be in
order to run the process I am trying to run.  The first one continues to run
full speed but the second runs very slowly.  

One reason that I think the swap file may be involved is that the VM setup
warns against setting up a vm with more than 3.X gigs of ram "or it will use
the swap file and performance will suffer".  I am guessing that the COMBINED
memory for the two vms is exceeding this value and so the second machine
started runs slowly.  Just a guess though.  Something is going wrong. 

That is in addition to the issue of the vm reboot though.  The vm reboot
appears to be something to do with both trying to run virtual disks where
the vd files are on the same hardware ram disk.  That too is just a guess.
I don't really know enough to figure out how to figure out the causes of
things like this, other than experimentation.


John W. Colby
Colby Consulting
www.ColbyConsulting.com 
-----Original Message-----
From: dba-tech-bounces at databaseadvisors.com
[mailto:dba-tech-bounces at databaseadvisors.com] On Behalf Of Gustav Brock
Sent: Wednesday, March 19, 2008 12:58 PM
To: dba-tech at databaseadvisors.com
Subject: Re: [dba-Tech] VMWare VM and shared RAMDISK

Hi John

Two instances of "the same" machine can easily run. I have had three web
servers running in parallel.
However, they must - of course - be configured to use different disk(file)s
...

/gustav

>>> jwcolby at colbyconsulting.com 19-03-2008 17:50 >>>
I got two instances of the same virtual machine going this morning.  A
simple copy of the directory is mostly all that has to be done.  There is
some sort of machine ID which VMWare complains is duplicated when the second
instance fires up, let VMWare correct that and then as the second instance
starts it says there are two machines with the same name on the network.
That required just setting the machine name to be different from the first
and rebooting that VM.

However the second machine will not run the software at the same time as the
first.  I set up virtual disks from the VM supervisor, one for each VM.
Each is a file on the hardware ram disk in the VMWare host machine.  I can
set them up, format them etc but when the second VM starts to run it
eventually reboots.  I am guessing that it is a conflict with the SATA
controller (when accessing the RAM disk) or some such.  It doesn't matter,
at this point I simply cannot run the second VM and have both access their
respective virtual drives on the Hardware RAM disk.  Sigh.

I guess that is why we do testing eh?

John W. Colby
Colby Consulting
www.ColbyConsulting.com 



_______________________________________________
dba-Tech mailing list
dba-Tech at databaseadvisors.com
http://databaseadvisors.com/mailman/listinfo/dba-tech
Website: http://www.databaseadvisors.com