jwcolby
jwcolby at colbyconsulting.com
Wed Mar 19 11:50:29 CDT 2008
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 -----Original Message----- From: dba-tech-bounces at databaseadvisors.com [mailto:dba-tech-bounces at databaseadvisors.com] On Behalf Of jwcolby Sent: Wednesday, March 19, 2008 1:07 AM To: 'Discussion of Hardware and Software issues' Subject: [dba-Tech] VMWare VM and shared RAMDISK Well I never got a software ram disk on the host showing as a shared ram disk on the VM, however... I have a Gigabyte iRam hardware ram disk which I have used with varying success for ages. It works just as advertised but Accuzip seems to have issues with using it sometimes. No se por que. The iRam is a 4 gig hardware ram disk that is SATA1 compatible. It plugs in to a PCI slot but only takes power from that. It actually communicates via an SATA port. Soooo... What I did was divide it into two partitions / volumes of 2 gigs apiece, though it is no longer clear that I even needed to do that. In the VM host software I added a new drive, which is just a virtual drive (file on a real disk). I made the new drive 2 gigs and placed the file on the RAM drive. I then turned on the VM. Once inside the VM I had to create a 2 gig partition and format it. I formatted it as an NTFS drive with 16K sectors (for speed reasons specific to Accuzip and what I am using it for). I then placed the files that I needed in a ram disk and started Accuzip and validated a 1 million record file. Voila, she works. I am getting 6.567 million records / hour, with a single processor VM machine. The VMWare runs on an AMD Phenom quad core with 8 gigs of RAM, Windows 2003x64. BTW, the VM is Windows 2003x32. On a real hardware machine with a dual core AMD, running Windows 2003x32 running that same iRam RAMDISK dedicated to that machine I was lucky to get 5.5 million records / hour, and actually averaged around 4 million - which at the time I thought was excellent. So basically by moving the Accuzip address validation software into a virtual machine, I INCREASED the speed of the software, using only a single core to do so. Not bad! 8-) Furthermore if you think about what I did I may be able to use the same concept to place virtual drives on a RAM disk in the host. However given that the hardware ram disk uses no host RAM the iRam might very well be a better solution anyway. I can now drop the memory dedicated to the VM since I was running a 700 meg RAM drive INSIDE if the VM. Since I am now using a virtual drive hosted on a hardware RAM drive on the host I can drop the VM memory by a like amount. My VM was using 3 gigs so if I drop the VM down to 2.3 gigs I may be able to run two VMs simultaneously. Or... On the VM host machine, run the vb.Net program that exports data from SQL Server out to the Accuzip VM. IOW run SQL Server 2005x64 and vb.Net, moving data out to Accuzip running on a virtual machine, and then back in to SQL Server, all on one single machine. We shall see. I just cut the VM back to 2.25 GBytes of memory and reran the address validation on the same 1 million records. I am still getting > 6.2 million records / hour. Now I need to run two VMs at the same time and see what I get. I will try that tomorrow. BTW running Accuzip native on the Windows 2003x64 with a 2 gig ram drive (carved out of memory) I was getting over 8 million records / hour, however that was also with all 4 cores available to the system and a memory RAM drive which is much faster. 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