Home > OS News > Improve Disk I/O Performances with VMware Workstation 5 Improve Disk I/O Performances with VMware Workstation 5 Submitted by Alessandro Perilli 2005-11-21 OS News 12 Comments “Even on a 2 GB RAM workstation (as mine) VMware virtual machines can run slowly. Too slowly sometimes. This can depend on a large amount of factors but we can reduce the number to 4 critical issues.” About The Author Thom Holwerda Follow me on Twitter @thomholwerda 12 Comments 2005-11-21 3:00 pm Robert Escue When I use VMware I create my virtual machines on a second disk (I use a USB connected 80 GB disk on my laptop) and with one virtual machine using 512 MB of memory the performance is good. 2005-11-21 10:17 pm segedunum When I use VMware I create my virtual machines on a second disk (I use a USB connected 80 GB disk on my laptop) and with one virtual machine using 512 MB of memory the performance is good. A second disk does it for me. I just thought that was totally sensible given the size of the VM files that you create…… 2005-11-21 7:38 pm Xen is faster and free as in freedom. 2005-11-21 7:55 pm BrianH You are trolling, right? You can’t use Xen to run a client OS that hasn’t been modified for it (such as Windows), unless you are running on hardware that most of us don’t have. For instance, I run VMware clients containing software that I would never trust to run on real hardware, such as copy-protected software, and none of that is open-source, obviously. Not all of us are free to pursue freedom, you know. 2005-11-21 8:03 pm When you run a benchmark inside the vm, the 1st obvious thing that hits you (or rather the performance) is disk I/O access. This is understandable since the vm disk is in fact a file on the host, so you end up with a two file system layer stack one on the other. The best way I’ve found to ease this is, like the first poster said, to use a second disk dedicated to the vm. Now this makes me wonder if you can tell vmware to use a partition instead. Finaly, to the anonymous poster, tell me, how fast does Windows run in your Xen? Come again? What do you mean you don’t know 2005-11-21 9:18 pm I’m running Win XP on a different partition (in fact a different physical drive than my Gentoo is using for / and /home), yet it’s still dog-slow. 512mbs where 320 go to VMware, 2000mhz atholn xp and SATA drive (Windows on PATA, where it was where i native-booted as well). I can’t even compare how it was to run it native and now.. with almost the same system, virtually it has only some 200mbs less of memory. Yet it’s really slow now. Worthless… 2005-11-22 1:37 am Performance most certainly depends on the host hardware and the guest OS. I have a 2U server with 3ghz dual Xeon CPU, 2gigs RAM and 350GB of SCSI RAID-5 storage running CentOS 4.2 with Win2k terminal server as the VM guest OS. I have merely 512MB dedicated to it and I have supported up to 7 simultaneous users (via RDP clients) running at what feels to be native speed- simply amazing. I honestly think Windows works better running as a VM than on real hardware. If it weren’t for reboots for patches, it would have uptimes as long as the Linux server- around 6 months or so. 2005-11-22 3:29 am I have no issues with performance on my desktop system (3.2GHz, 2GB RAM, 10,000RPM SATA drives). The VMs run fast enough that I don’t even think about native speed. On my laptop, there is definitely an I/O issue. The laptop has 2GB RAM, and a 7200 disk, yet I notice a big difference between the 2 hosts (both running Linux). 2005-11-22 1:27 am as i understand it – you will be able to run windows under xen3 on the forthcoming cpus from intel/amd. also with xen – you can run off a partition or a file – easily. 2005-11-22 9:46 pm “If it (windows) weren’t for reboots for patches, it would have uptimes as long as the Linux server- around 6 months or so.” you get the insane comment of the year award. yea if you dont use windows – let your computer just sit there and collect dust – but if your are opening and closing windows and applications the system will slow down a lot quicker than your 6 months reboot uptime. i reboot everyday even with 1 gb of memory. i want a speedy and stable system. 2005-11-23 9:48 am As others have already said, if your machines specs are high enough (Dual 2.8Ghz Xeon, 2GB RAM, 36GB + 74GB SCSI U320 / 300GB 7,200 PATA drives) you can’t tell that your running a VM (BTW, I keep all of my VM images as files on the PATA drive). I’ve also noticed that the VMs are more responsive if you run VMWare on a Linux (Suse 9.3) host compared with Windows (2000/2003 or XP). In comparison, my Dell Latitude 600 (2Ghz Dothan, 2GB RAM, 60GB 5400rpm drive) laptop also does reasonably well, with the exception of I/O access. Loading Eclipse takes 2x longer on the laptop. 2005-11-23 1:08 pm I run vmware 5 @ work with an pentium III 1Ghz with 1GB of memory. I have two virtual Servers (w2k) and one virtual workstation (also w2k) to te eumlate a Active Directory Forest. When all machines are up and running there is still accteptable speed. All machines are asigned 128 MB memory.