Tuesday, August 26, 2008

DFW Layover

I was actually just testing the Centro to make sure it would sent the Blogger. Something is wrong, however, as this image is hosted at Sprint. They'll delete it after 30 days.

Not acceptable. I'll try again.

Friday, August 22, 2008

Virtualization Round-up

Over the course of the last year, I've done allot of experimenting with virtual system platforms. I think I've decided the best direction for my efforts. These observations are driven by two factors: ease of set up and capacity for remote administration.

I've done business with two Virtual Private Server (VPS) services, which were oddly named VPSland and VPSlink. I actually ditched VPSland because the provided CentOS, which was highly unstable. (Yes, yes, yes... I've heard all your arguments before: "CentOS is just RedHat". I've worked with RedHat for almost ten years: You're wrong.) What we really want to talk about is OpenVZ at VPSlink.

The OpenVZ platform does not offer VMs a swap file. This means that each VM needs access to large amounts of physical RAM. Given that disk is cheaper than RAM, this significantly limits VM density on the host. In my case, I could not even run RPM commands unless I had 256MB of RAM. Once I converted to Xen, everything ran on 64MB.

Vmware Server 2 Beta
Wow, was I disappointed in this product. All management is done via a web interface that is slow, clunky, and optimized for Windows desktop use. As a result, it posed several challenges. First, it required a 12meg browser plugin. Unfortunately, if I wasn't on the LAN, the plugin would time out.

The next problem was getting all the pieces needed for the install. Vmware provided an RPM, but no indication as to the dependencies for the RPM. Once the RPM was installed, it turns out there are additional, unchecked dependencies. The good news, however, was that all the hardware was recognized. Speaking of recognized hardware...

Vmware ESXi 3.5
Vmware recently announced they were dropping the license requirements for the ESXi server in the standalone mode. This created allot of excitement. I downloaded the ISO and quickly discovered that only "select SATA controllers" are supported. Not mine.

With no hardware to run it, ESXi was less than exciting.

Vmware VI3 ESX+VC
By far, the VI3 product set is the hands down winner... If you have $15,000 to spend. My budget is in the $150 range.

I'm sorry to say, Linux para-virtualization with full-virt support takes wins. Easy to deploy, remote console available via X11, command line and GUI support. Text based Linux installation is available within an unmodified SSH session. About my only downside is that the memory allocation is not as dynamic as I'd like.

Bottom Line
Is it any surprise the Linux guy didn't test Microsoft? No, not really. Is it a surprise the RHCE guy picked the platform included with Fedora? Maybe-- but in the end, it was stability and ease of access that won the day.

Thursday, August 14, 2008

X11 Forwarding to Vista: Pt 2

Wow. The performance on the Cygwin only X11 tunneling is horrible. I was able to improve performance significantly, however, by going back to PuTTY. In the PuTTY settings for the server, I went to Connection / SSH / X11 and checked Enable X11 Forwarding.

Now, launch Cygwin, PuTTY to target, launch graphical application. Performance still sucks, but it works. Hey, its not like this is the only application that has taken a hit under Vista!

Wednesday, August 13, 2008

Linux RAID0 (striped) Performance

As I continue with the process of reoganizing my virtualization servers, I ran a quick test on my drives in my other Xen box. Originally, I had /home on a RAID1, but wanted to see if I could truly get a boost out of a RAID0. Three tests: an LVM volume on a single disk, a RAID1 mirrored across two disks, the same two partitions in a striped RAID 0:
[root@baltar xen]# hdparm -Tt /dev/vg0/test /dev/md0
  Timing cached reads: 416 MB in 2.01 seconds = 207.25 MB/sec
  Timing buffered disk reads: 28 MB in 3.09 seconds = 9.05 MB/sec
  Timing cached reads: 416 MB in 2.02 seconds = 206.40 MB/sec
  Timing buffered disk reads: 32 MB in 3.05 seconds = 10.50 MB/sec
Notice the buffered speeds are very close. This is because the LVM is on /dev/hda, as is the first element of the RAID1. (These are old disks on an old Celeron CPU.)

Now we rebuild the same two partitions into a RAID0. The disks are on separate controllers (/dev/hda and /dev/hdc) so we expect a boost in throughput:
[root@baltar xen]# hdparm -Tt /dev/md0
  Timing cached reads: 416 MB in 2.00 seconds = 207.91 MB/sec
  Timing buffered disk reads: 68 MB in 3.05 seconds = 22.30 MB/sec
Yeow! Look at those numbers: better than double.

I'm convinced.

Vmware: Reconcile Inventory with Disk

Interesting problem: As we know Linux / Unix don't like file names with spaces. The Vmware GSX, Server 2 Bate, and ESX have a Linux command line, but can support spaces in virtual machine names. This makes it difficult to reconcile VMs in the inventory against those on the storage.

Here's a one-line to handle it:
find -name *.vmx | 's/ /\\ /g' |
  xargs grep -i "display"

Output will show directory path, configuration filename, and inventory name for all VMs. If executed from /vmfs/volumes, it will span shared storage as well.

Tuesday, August 12, 2008

X11 Forwarding to Vista

I'm just getting around to turning on X11 forwarding to my Vista laptop. As a result of certain work related issues, I thought I was going to use Putty as the SSH client. I've done with with other clients, and had used Cygwin as the X11 emulator on XP. Of course I couldn't get Putty and Cygwin to play, but then I found another option.

1. Download Cygwin setup. Launch same.
2. When prompted for packages select Net/openssh and X11.
3. Once installed, launch Cygwin. This will open a text window, AKA: CLI.
4. Type startx. This will open an xterm window. (Oddly, it failed several times before working. I'll have to work on that.)
5. Access the remote system:
ssh -X user@server
6. After login, type xclock as a test.


I just found out that the WinSCP guy has a portable version of his Windows based SCP client that is a single executable which can be run from a flash drive, without being installed on the system. Check out:


Monday, August 11, 2008

Vmware Server 2 Beta

Ran into an interesting problem attemptting to install Vmware Server 2 Beta. I've been working almost exclusively with ESX for the last few months and decided to replace my Xen system with the free Vmare product. My motivation was to experiment with the user interface.

The RPM imploded during the first install. I guessed the download was corrupted. I downloaded the file a second time, but it refused to try a second install. Since it was not in the RPM database, I knew it had to be some file system droppings.

First, I cleared some files from /usr/bin:
rm -rf /usr/bin/vm*
That didn't work, so the next step was to nuke the application directory:
rm -rf /etc/vmware/*
That got it. The RPM is installed. Now we have to figure out how to use it.