Questions[vmware-esx](server)

VMware allows to extend the size of a virtual disk online - when the VM is running. The next expected steps for Linux system are:

1. extend the partition: delete and create a larger one with fdisk
2. extend the PV size with pvresize
3. use free extents for lvresize operations
4. and then resize2fs for file system

But I am stuck on the first step: fdisk and sfdisk still display the old size for the disk.

My disk is a SCSI virtual disk connected thanks to the virtual LSI Logic controller.

How to refresh the virtual disk size and partition table information available in Linux kernel without reboot ?

As far as I know all that steps are possible for a running Windows, without reboot and even without any user actions thanks to VMWare tools. On Linux, I expects to do all steps online too and I already know steps 2, 3 and 4 work online. But the first one - change partition size declared in the partition table (still) seems to require a reboot.

Update: My system is a Debian Lenny with kernel 2.6.26 and the disk I have extended is the main disk with a large PV containing the "root" LV for "/".

On a VMware ESX setup what is the difference of these options?:

• a Linux VM with 1GB RAM and 1GB swap partition and the VM uses 1.5 GB ram
• a Linux VM with 1GB RAM and no swap partition and the VM uses 1.5 GB ram

I mean, in both cases swap is being used;

• in the first swap is done to the linux swap partition
• in the second case, VMware will swap 512MB to the VMware storage pool.

So are there any point in giving Linux VM's a swap partition?

I've been using VMWare for many years, running dozens of production servers with very few issues. But I never tried hosting more than 20 VMs on a single physical host. Here is the idea:

1. A stripped down version of Windows XP can live with 512MB of RAM and 4GB disk space.
2. $5,000 gets me an 8-core server class machine with 64GB of RAM and four SAS mirrors.
3. Since 100 above mentioned VMs fit into this server, my hardware cost is only $50 per VM which is super nice (cheaper than renting VMs at GoDaddy or any other hosting shops).

I'd like to see if anybody is able to achieve this kind of scalability with VMWare? I've done a few tests and bumped into a weird issue. The VM performance starts degrading dramatically once you start up 20 VMs. At the same time, the host server does not show any resource bottlenecks (the disks are 99% idle, CPU utlization is under 15% and there is plenty of free RAM).

I'll appreciate if you can share your success stories around scaling VMWare or any other virtualization technology!

Can VMWare ESX or ESXi be installed and used inside a virtual machine?

It can be installed inside VMWare Workstation or Server, but then it doesn't work; the main symptoms are:

• It runs REALLY slowly.
• It lets you create VMs, but when powering up them it gives an error stating "You may not power on a virtual machine in a virtual machine".

The idea of having a small footprint hypervisor as the primary OS on a laptop or desktop where every "real" OS is a guest appeals to me. Now I realize this software is more typically used on blades and the other servers but can it be done on a normal PC? Should it be? What requirements are there (eg hardware/BIOS/chipset)? Is there a performance impact for doing so? Is it a good/bad idea?