Virtualization: September 2009 Archives

Redhat Enterprise Server 5 on VMware ESX 4 - including PVSCSI boot

By
Pascal Gienger
on September 24, 2009 8:48 PM | | Comments (0) | TrackBacks (0)
redhatbumper.png
A step-by-step instruction manual how to install RHEL 5 using a paravirtual SCSI boot device in VMware is described here:

http://southbrain.com/south/tutorials/installing-redhat-enterprise-5.html

Comments are welcome!

rtc! Sun xVM: Wrong timezone offset in PV DomU?

By
Pascal Gienger
on September 22, 2009 9:05 AM | | Comments (0) | TrackBacks (0)
Running paravirtualized Linux Kernels as DomU on Sun xVM/Xen 3.4.2 I had the "little" problem that timezone offsets are not correct. My machines are located in Germany so the Timezone in Linux is "Europe/Berlin". The result:

OpenSolaris Dom0: Tuesday, September 22, 2009  7:06:38 AM UTC
Linux SLES 11 DomU: Tue Sep 22 11:06:38 CEST 2009

"CEST" means Central European Summer Time, and the offset should be two hours, not four!

The solution:
Dom0's real time (hardware) clock has to be set to UTC!
Using Linux as Dom0 this would be a simple  "hwclock --utc" call. On OpenSolaris the command is:

rtc -z UTC

The result will be written permanently in /etc/rtc_config.
Don't forget to do a
 
svcadm disable ntp; ntpdate ...yourtimeserver...; svc enable ntp

DomU Linux machines are immediately changing to the right time (9:06 CEST in the example above).

How storage works in VMWare ESX?

By
Pascal Gienger
on September 20, 2009 11:19 AM | | Comments (0) | TrackBacks (0)
As opposed to the Xen/Sun xVM storage virtualization is done in the ESX Kernel (the simple case where no dedicated hardware storage is reserved and defined as passthrough for the virtual machine):

esxstorage-480.png
Continue reading How storage works in VMWare ESX?.

How storage works in Sun xVM/Xen?

By
Pascal Gienger
on September 19, 2009 10:15 PM | | Comments (0) | TrackBacks (0)
In the HVM case it is a little bit like this (simplified):
xenstorage-hvm-480.png
Continue reading How storage works in Sun xVM/Xen?.

Redhat Enterprise 5 Server in Xen!

By
Pascal Gienger
on September 17, 2009 7:35 PM | | Comments (0) | TrackBacks (0)
Yes we know, Redhat Inc. has its own virtualization technique named KVM but nevertheless it installs just painless in a Xen environment.

I spent 15 minutes with an interactive install in a paravirtualized Sun xVM/Xen domain and this is very fast.

I described the steps in my little article: Installing Redhat Enterprise Linux 5 on Sun xVM

It appears in the Redhat network as "Para-virtualized" which is 100% correct:

redhatoverviews.png



Virtualization techniques and approaches

By
Pascal Gienger
on September 15, 2009 3:42 PM | | Comments (0) | TrackBacks (0)
virtualization-hypervisor-example-60.pngI began to compare some different approaches to virtualization available and to visualize them with graphical pictograms.

I am appreciating your feedback whether I achieved that goal or not.

The following articles are available so far:

  1. Why virtualization?
  2. Userspace-based virtualization (the easy way)
  3. Xen: Hypervisor-based virtualization
  4. ESX: Hypervisor-based virtualization
  5. Solaris Zones: A sharing approach
  6. Hybrid methods: KVM

ESX 4 (VMWare): SUSE Linux with paravirtual SCSI controller

By
Pascal Gienger
on September 11, 2009 1:58 PM | | Comments (0) | TrackBacks (0)
[Remark: With Redhat Enterprise Server 5 it is a little bit more difficult, creation of the initial ramdisk image is not so straightforward: Click here for the redhat howto]

works out of the box:

SCSI subsystem initialized
VMware PVSCSI driver - version 0.0.0.6
pvscsi 0000:03:00.0: PCI INT A -> GSI 18 (level, low) -> IRQ 18
pvscsi: found VMware PVSCSI rev 1 on bus 3:slot 0:func 0
pvscsi 0000:03:00.0: setting latency timer to 64
pvscsi: enabled MSI-X
scsi0 : VMware PVSCSI storage adapter rev A, 256 reqs (8 pages), 1024 cmps (8 pages), cmd_per_lun=64
scsi 0:0:0:0: Direct-Access     VMware   Virtual disk     1.0  PQ: 0 ANSI: 2
 sda: sda1 sda2 sda3
if you do the following steps:



Continue reading ESX 4 (VMWare): SUSE Linux with paravirtual SCSI controller.

vSphere 4 ESX vs Sun xVM Xen 3.4.2: Windows 2003 SP2

By
Pascal Gienger
on September 11, 2009 7:46 AM | | Comments (2) | TrackBacks (0)
driversvmwarexen.png
I am not a Windows guy, I admit, but in our data center there are many Windows 2003 Server installations (32bit) and we are going to virtualize them.

Management's choice is VMWare vSphere 4 (ESX 4) but nevertheless I wanted to know how Sun xVM/Xen behaves compared to ESX. Forget all that nice Management tools offered by vmware, the only thing I was interested in is the performance feeling when actually using them.

The picture at the right (click on it to enlarge) shows the hardware list of the two "brothers": To the left you'll see the xVM DomU with paravirtualized disk and network drivers, to the right there's the vSphere ESX virtual machine with a paravirtualized SCSI disk device (and an IDE boot disk, you cannot boot in ESX from a paravirtualized disk).


Continue reading vSphere 4 ESX vs Sun xVM Xen 3.4.2: Windows 2003 SP2.

Assigning CPUs works even in Domain-0!

By
Pascal Gienger
on September 2, 2009 6:45 PM | | Comments (0) | TrackBacks (0)
Just a small note:

It was just a test, but it worked!

You can control the number of CPU cores Dom0 uses (named "Domain-0" in the Sun xVM environment).

This command:

# virsh setvcpus Domain-0 2

results in that:

Sep  2 18:35:16 pgt01 unix: cpu0: externally initiated on-line
Sep  2 18:35:17 pgt01 unix: cpu1: externally initiated on-line
Sep  2 18:35:17 pgt01 unix: cpu2: externally initiated powered-off
Sep  2 18:35:18 pgt01 unix: cpu3: externally initiated powered-off

Crazy.
OS is OpenSolaris snv_121, which was bfu'd from snv_118.

(Setting the memory use and max memory use via virsh setmem and virsh setmaxmen do also work as expected, the system begins to swap out pages and/or flushes zfs cache data on disk).

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