I've come across an insanely brilliant blog post on iSCSI. One of the best technical blogs I've seen in a long time. Actually one of the best technical blogs I've ever seen! I took some time out and sat down with a mug of coffee to read the post in detail. I found this blog post every interesting and in good time as I've actually started on the iSCSI shared storage section of my book on "Building a Low cost VI Environment" just yesterday.
Ok, I do have to say that a lot of the stuff in the blog post is "too heavy" for my new book as the aim for my book is to build a low cost lab VI environment, not an enterprise VI environment. However I do think that a lot of what they have in the blog post can be used to optimize even a low cost lab environment. I've been using Openfiiler for a while now and I will certainly be looking at improving my home VI environment's iSCSI implementation. In my new book, the shared storage section is based iSCSI provided by Openfiler 2.3. I will definitely look into improving the iSCSI section of the book by looking into some things like "jumbo frames" mentioned in the blog post!
Thanks to Chad Sakac (EMC), Andy Banta (VMware), Vaughn Stewart (NetApp), Eric Schott (Dell/EqualLogic), and Adam Carter (HP/Lefthand) and David Black (EMC) for this great post.
Administrators that's got some experience in running Linux guest operating systems in virtual machines, may know that the time of the guest OS can drift by several hours per day. Normally, in my experience the time in the guest OS runs too fast. This can have serious implications on some services that these servers provide, such as Mail/Spam relays and web servers.
VMware has now released a very good KB article on best practises for Linux Guest OS time keeping, with a table of kernels and their parameters.
The KB article is a must read for those who have Linux guests. You can find VMware KB Article 1006427 here
As we are now busy doing P2V conversion of most of our physical servers I needed to use the Consolidation function in vCenter (previously known as VirtualCenter) to assess the workload of the physical servers (CPU and Memory Usage).
I was surprised to see that the "Consolidation" button disappeared from my VI Client! I checked if it was installed as a plugin and it was. I also checked if it was enabled and again, it was. However, the button was not there!
I found that although the plugin can be installed and enabled in the VI client, it is also a requirement to have VMware Capacity Planner installed on the vCenter server. I checked my vCenter server and confirmed that it was indeed already installed.
Here's the fix:
It seems like the Consolidation Function for vCenter is disabled by default in the vpxd.cfg file. To enable the consolidation function, do the following:
On the vCenter server, edit c:\Documents and Settings\All Users\Application Data\VMware\VMware VirtualCenter\vpxd.cfg
(I'm still using VirtualCenter 2.5.0 Build 119598, so your path could be ...\vCenter\cpxd.cfg? I'm not sure!)
You will find the following three lines:
Change them to read:
Restart the VirtualCenter service using the Services.msc MMC snapin in Windows. The Consolidation Button should now be available in your VI, Providing that that it's installed and enabled and that VMware Capacity Planner is installed on the vCenter server.
I've been told about a flash video that demonstrates some of the features included in Citrix XenServer. Some of the features look very handy indeed. But, will it be good enough to give VMware a good run for their money? Well, unfortunately I am not in a position to comment on that, as I've never touched XenServer before.
Anyway, have a look at the flash video