Monday, May 30, 2011

Fantasmic Nouveau Retro Future Robot Art

Check out the web site of really cool works from artist Nemo Gould.

Sunday, May 22, 2011

Andre California Champagne

I didn't want it, but got it anyway. I'd had it a zillion years ago, and knew what to expect. This is a wine you buy for the storybook wedding where you are judging the quality of the event by the number of people you invite.

I only invited Ronald and Nancy Reagan.
    They politely declined the invitation.
        Something about being busy being President, at the time.

So, if you have to buy 24 bottles of sparkling wine for people you don't really care about, buy this. Otherwise, invite 1/4 the number of people, and spend four times as much on real Champagne or good Presecco.

3 of 10

Gerd Anselmann Dornfelder

Every time I go wine shopping, look at the German reds. Unfortunately, the reds the German's send us, are far lacking what they keep for themselves. As a result, when people think of German wines, they think white (Riesling), not red. The reason: climate. The colder the climate, the more difficult it is to grow red then white.

I've suffered many bad German imports-- most only slightly less disgusting than taking a can of frozen grape juice, adding a cup of corn syrup, and diluting with a cup of pure grain alcohol. And even though Spatburgunder is Pinot Noir, most Californians are better.

Dornfelder is a unique varietal, native to Germany. Again, the climate makes it sweet, but this one was only mildly so. The flavor is similar to a Lambrusco, but the stand out for this wine was the body and color: Wow!

I'll be stocking this one, especially for the price of about $15. A firm 8 of 10.

Sunday, May 01, 2011

RHEL 6 Virtualization, Memory

There are two memory settings presented in virt-manager: Allocation and Maximum. The Allocation setting is what will appear in /proc/meminfo and top. The Maximum is what can be used to boot the VM. Interestingly, the kernel will refuse to boot with out enough RAM, but once booted, will run with significantly less.

The Maximum value needs to be more than 348MB. Any lower, and boot time is noticeably slower due to swap activity.

The Allocation value needs to be more than 148MB. The VM won't crash until the allocation is about 115MB, but there are several factors that could effect that number. Obviously, 148MB may not meet a every VMs needs, but it seems to be the lowest reasonable limit.

Keep in mind, the Maximum is always allocated to the VM at boot time, and them lowers to the Allocations, so don't set it too high. The Allocation can be dynamically changed for a running VM, but cannot exceed the Maximum. Any changes to the Maximum require a reboot.

RHEL 6 Virtualization, Paravirtualization

Paravirtualization is a big deal. It is avoided by VMware, is alchemy in Citrix Xen, and is cryptically alluded to in RHEL 6. Yet, for those of us that are almost exclusively Linux, the performance and density advantages are huge. Even Windows XP performance is noticeably improved running "para-virt". (As for Vista and Win7... they're both hogs, no matter what.)

In ten words or less, paravirtualization improves performance by loading a version of the operating system optimized for the host's hypervisor.

In the RHEL 6 Virtualization guide Chapter 8, they state that para-virt does not work with KVM. This would imply that there is no way to optimize a RHEL 6 VM on the RHEL 6 platform. Given that, why not just run VMware?

Yet in Chapter 11, they mention that para-virt drivers are automatically loaded and installed for RHEL 6 VMs and Linux VMs based on the 2.6.27 or newer kernel.

So... Which is it... Para-virt yes or para-virt no?

Survey says: Kernel no, drivers yes. But, of course, there's a catch.

Once the VM is installed and running, execute an lsmod | grep virtio. Look at the last line. The items at the right of the numbers will indicate which para-virt drivers are used. You want four of them, but may only have three. Depending on how the VM accesses the outside network, the virtio_net driver may be missing.

To enable virtio_net, a specific sequence of events must be followed:
1. Power off the VM
2. From virt-manager, Open the VM
3. Select View and Details
4. Select NIC
5. Change Device model to "vrtio"
6. Apply, exit, and Run the VM
Upon boot, the virtio_net driver should be listed.

Call it a bug, but if you try this with the VM powered on, it will claim to work, but will not.

As for performance without a para-virt kernel, I am still a little skeptical.

The President's Speech