Monthly Archive: April 2012

Apr 30

With vSphere 5.0 and HA can I share datastores across clusters?

by

April 30, 2012

I have had this question multiple times by now so I figured I would write a short blog post about it. The question is if you can share datastores across clusters with vSphere 5.0 and HA enabled. This question comes from the fact that HA has a new feature called “datastore heartbeating” and uses the datastore as a communication mechanism.

The answer is short and sweet: Yes.

For each cluster a folder is created. The folder structure is as follows:

/<root of datastore>/.vSphere-HA/<cluster-specific-directory>/

 

The “cluster specific directory” is based on the uuid of the vCenter Server, the MoID of the cluster, a random 8 char string and the name of the host running vCenter Server. So even if you use dozens of vCenter Servers there is no need to worry.

Each folder contains the files HA needs/uses as shown in the screenshot below. So no need to worry around sharing of datastores across clusters. Frank also wrote an article about this from a Storage DRS perspective. Make sure you read it!

PS: all these details can be found in our Clustering Deepdive book… find it on Amazon.

“With vSphere 5.0 and HA can I share datastores across clusters?” originally appeared on Yellow-Bricks.com. Follow us on Twitter and Facebook.
Available now: vSphere 5 Clustering Deepdive. (paper | e-book)

Tags: , ,

Permanent link to this article: http://www.startswithv.com/2012/04/30/with-vsphere-5-0-and-ha-can-i-share-datastores-across-clusters/

Apr 25

What is das.maskCleanShutdownEnabled about?

by

April 25, 2012

I had a question today around what the vSphere HA option advanced setting das.maskCleanShutdownEnabled is about. I described why it was introduced for Stretched Clusters  but will give a short summary here:

Two advanced settings have been introduced in vSphere 5.0 Update 1 to enable HA to fail-over virtual machines which are located on datastores which are in a Permanent Device Loss state. This is very specific to stretchec cluster environments. The first setting is configured on a host level and is “disk.terminateVMOnPDLDefault”. This setting can be configured in /etc/vmware/settings and should be set to “True”. This setting ensures that a virtual machine is killed when the datastore it resides on is in a PDL state.

The second setting is a vSphere HA advanced setting called “das.maskCleanShutdownEnabled“. This setting is also not enabled by default and it will need to be set to “True”. This settings allows HA to trigger a restart response for a virtual machine which has been killed automatically due to a PDL condition. This setting allows HA to differentiate between a virtual machine which was killed due to the PDL state or a virtual machine which has been powered off by an administrator.

But why is “das.maskCleanShutdownEnabled” needed for HA? From a vSphere HA perspective there are two different types of “operations”. The first is a user initiated power-off (clean) and the other is a kill. When a virtual machine is powered off by a user part of the process is setting the property “runtime.cleanPowerOff” to true.

Remember that when “disk.terminateVMOnPDLDefault” is configured your VMs will be killed when they issue I/O. This is where the  problem arises, in a PDL scenario it is impossible to set “runtime.cleanPowerOff” as the datastore, and as such the vmx, is unreachable. As the property defaults to “true” vSphere HA will assume the VMs were cleanly powered off. This would result in vSphere HA not taking any action in a PDL scenario. By setting ”das.maskCleanShutdownEnabled” to true, a scenario where all VMs are killed but never restarted can be avoided.

If you have a stretched cluster environment, make sure to configure these settings accordingly!

“What is das.maskCleanShutdownEnabled about?” originally appeared on Yellow-Bricks.com. Follow us on Twitter and Facebook.
Available now: vSphere 5 Clustering Deepdive. (paper | e-book)

Tags: , ,

Permanent link to this article: http://www.startswithv.com/2012/04/25/what-is-das-maskcleanshutdownenabled-about/

Apr 11

Startswithv x Dress-Lace Inc Cold Shoulder Lace Dress

by

April 11, 2012

Startswithv x Dress-Lace Inc Cold Shoulder Lace Dress In Safari Print With Crochet Insert Sleeves

Wearing fun and flowing dresses is all part of the fun of war weather dressing. This http://www.dress-lace.com/ x startswithv clothing is one of those fun lace dresses which also offers a funky and look which is very hip. This dress features a cut which has become very popular this year. This is the cold shoulder cut which shows off the upper arm and shoulder area. There are delicate crochet inserts which have been added to the lower sleeve wraps. The scoop neckline and spaghetti straps of this dress add to the fun and free flowing style of this dress. The cross back detailing of the dress offers a stylish visual to the back of the dress. The 100% rayon fabric of the dress features a safari print on a black background. The body of the dress is cut in loose style which still offers a regular true to size fit. This is a hand wash lace dress which you will want to wear time and again.

This post has no tag

Leave comment

Permanent link to this article: http://www.startswithv.com/2012/04/11/startswithv-x-dress-lace-inc-cold-shoulder-lace-dress/

Older posts «