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VMWare Performance tips

these are tested from experience…. (the following is true on vmware server 1.0.6 on a linux host)

  • Always use only 1 Virtual CPU - i have found that most times even if you have heaps of cores to spare on the host, a single virtual core is faster.
  • Set the memory to the recommended level when possible - 256Mb sounds shit when you have 4gb, doesn’t matter - set it to 256Mb (increase only if excessive paging on the guest). Let linux and vmware manage the memory, in most cases it does a much better job than windows. Do not disable memory page trimming on any of the guests, this gives more memory back to the host to cache other more important activity (disk etc)
  • Never use 2gb split files for the virtual disk unless you have to transfer the vm onto a file system that doesn’t support larger files.
  • Load the latest drivers for your NIC on the host
  • Be nice to your physical disk - do not load all your VM’s on a single drive - the HDD is the slowest part of the system, dont saturate it. I use either a raid 0 running multiple vm’s (with backups) or dedicated drives per set of vm’s. This excludes enterprise level raids which can handle much higher level of simultaneous requests.
  • Install vmware tools on all guest machines

watch your pings - ping your guests… they should never loose a ping. If they do you are loading the cpu to high and the host cannot process the network queries. As above use only one virtual cpu. Also ensure you have the latest network driver loaded for your NIC on the host.

ZFS - Error 16 : Inconsistent filesystem structure

Oh no. I’ve managed to get this error before. And it was right after i applied compression to the rpool zfs filesystem. Upon the next reboot i was greeted with this error message;

Error 16 : Inconsistent filesystem structure

For me it was a show stopper and i had to go into recovery. So i’ve learnt my lesson - Not to touch the rpool zpool.

I was lucky enough to have put my data within a zfs filesystem (rpool/virtual) i created within the default rpool zpool.  I use this spot for my VirtualBox virtual machines.

ZFS basics

I’ve had a play with WHS but eventually got annoyed with its lack of performance. Yes i know its not built for performance and typically is used just as a backup / simple store with duplication as redundancy, just i couldn’t stand the speed of the thing. If you were ever unlucky enough (even post power pack 1) to do a copy during the “data moving” the performance was even worse. On a positive note nothing beats it if you have a heap of non-similar sized disks that you want to put together (with redundancy) as a single shared storage pool.

ZFS compression types

ZFS compression as of OpenSolaris 2008.11 has a few types to choose from.

lzjb (default) | gzip | gzip-[1-9]

They are used via the zfs set compression=gzip poolname command.

The following test was quickly done out of personal interest - and is in no way scientific!

I have a AMD cpu with 3 cores (2.4Ghz). The data i copied to each of the shares consisted of video / documents / pictures and music. The first test i have done is based on compression only (i have not measured throughput)

OpenSolaris - Autologon

There are two ways to setup the auto login for OpenSolaris (2008.11);

One - You can fire up the GUI using gdmsetup. Update : this didnt actually work when i tried it recentely - it might not be in this release of opensolaris.

Two - go to /etc/x****11/gdm/custom.conf (in newer releases its just /etc/gdm/custom.conf) and manually modify the required fields in the [daemon] section and add the following;

[daemon] AutomaticLoginEnable=true AutomaticLogin=username