I recently had the joys of helping deal with an All Paths Down (APD) situation which presented itself when removing a LUN from all the hosts in a cluster. If you do not detach the device first, which will also initiate an unmount operation before you physically unpresent the LUN from the ESX, it causes an APD situation to happen. ADP is when ESXi server no longer has any active paths to a device. When the device is no longer present and you rescan the adapters ESXi server will still retain the information on the removed devices and hostd will continue to try to open a connection to the disk device by issuing different commands like read capacity and read requests to validate the partitions tables are set. If SCSI Sense codes are not returned from a device (you are unable to contact the storage array, or the storage array that does not return the supported “SCSI codes”), then the device is in an All-Paths-Down (APD) state, and the ESXi host continues to send I/O requests until it times out.
How do we measure success? This seems like it should be an easy question to answer but is it? Success itself is a dynamic variable that can be defined in several different ways from a promotion or even recognition from your peers. Now what about a successful cloud implementation or implementation in general? How would you define success? The true definition of implementing is to fulfill; perform; carry out: or to put into effect according to or by means of a definite plan or procedure. For the design and implementation team, success could be defined by the completed installation design, deployment and verification testing of all functionality as defined in the statement of work.
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Since the start of the Windows 8 Public Beta, there has been a great deal of discussions and comparisons galore. There have been points made that Microsoft Hyper-V will be good enough to draw good consideration in companies looking to the future. For me personally, feature comparison was not my first consideration. One measurement that I consider is the eco-structure of the technology or in other words, how large is the 3rd party partners and products supporting both the technologies?
When we look for patterns from the past, sometimes we can really get a good idea of what the future might entail.
If you take a look at the way VMware has rolled out licensing changes during each of the major releases you can see a pattern and get an idea of what the future may bestow on us. When Virtual Center was first released, vMotion and vSMP were licensed separately from Virtual Center as an add-on for Virtual Center.
Once VMware ESX3 was released, vMotion and vSMP pretty much became a standard feature included in ESX3. Virtual Center was still sold separately and then VMware presented three licensing models for VMware ESX3.
There has been a lot of buzz and coverage about Windows 8 since its consumer preview. There will be some very cool features with this release and one feature that really stands out with me is that Microsoft added an additional supported processor type in that Windows 8 will run on Intel, AMD and now ARM based processors. That gives Windows 8 the ability to run on desktops as well as mobile phones and tablets.
Microsoft Windows Server 8 Beta has been open to the public and there is one feature that really caught my eye. With Windows Server 8 you can now have basic PowerShell console over HTTPS with Microsoft Windows PowerShell Web Access (PSWA). Think about the possibilities with that. You get an email that there is an issue and you could start PWSA on your phone, or other device, and resolve the problem or request.
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Should software licensing be completely based off of the hardware MAC address of the NIC and or UUID of the mother board? This process worked very well before the introduction of virtualization but now that virtualization has become more prevalent in most environments. I think software venders really need to reconsider how they are going to license their software although it seems that some companies have not bought on to the idea of virtualization and would prefer to continue to support their product type to a specific hardware platform that the vender put together and shipped out. Can software venders hope to survive and remain current without embracing virtualization? I think the answer to that question is going to be no in the long run.
I was involved with the design and deployment of a small proof of concept that would introduce virtualization to a local SMB in my area. The idea was to build them something small that they would grow into and at the same time demonstrate all the really cool things that virtualization can bring to the table. I built a couple of hosts and deployed virtual center virtually, as well as added the VMware Management Appliance and the VMware Mobile appliance. It is really fun to get a chance to introduce virtualization to people, it is almost as fun as bringing a child to a candy store. Showing the client what they can do with virtualization as well as what they can do on their iPad is just priceless.
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