VMFS Volume is locked

This is an unusual situation that I came across today, the exact issue that I faced was related to an issue with a Riverbed Steelfusion appliance but could easily happen to a normal VMware environment.

With Riverbed Steelfusion, we present out a LUN to a remote location as iSCSI… this remote location creates the datastore etc. as with a normal environment and therefore place a lock on the LUN.  In our situation today, the remote location had a failure of the Riverbed Steelfusion appliance (something that doesn’t happen often) and we had to go through and present the LUN and virtual machines out of our data centre to allow the location to continue working whilst waiting for a replacement unit.

When trying to mount the LUN into our data centre environment we received an alert to say that the volume was locked… which makes sense because it wouldn’t have been released properly from the remote location.

A similar issue could occur in a data centre where a host has placed a lock on a LUN and has a failure, meaning that the lock doesn’t get released.

So, what do we do about it… well, the first thing to do is to try and reboot each of the hosts that have the LUN presented to it, as this could release the lock.

If you are still experiencing issues where the LUN is locked, then you need to break the lock using the following information… (please note that you should make sure that no other hosts are connected to the LUN as this will break to connection for all hosts)

vmkfstools -B /vmfs/devices/disks/disklunid

The LUN ID should be something similar to:  naa.60060160b3c018009bd1e02f725fdd11:1     please note that this is with the :1 at the end.

Full details of the process can be found here:



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About the Author


I have been in IT for the past 15 years and using virtualisation technologies for around the past 8 years. I started, as quite a lot of people do, working with PCs after playing with such iconic systems like the ZX81, ZX Spectrum and then progressing through 386s, 486s, Pentiums etc. After being headhunted at sixth form to work for a small company based around Hertfordshire, UK. I began working with small businesses and gaining a lot of hardware experience. Three years later, after helping to increase the size of the business, I needed to gain exposure to a larger environment to progress my own career. I joined a large manufacturing company around Electronic Test and Measurement which progressed my skills onto more PC work, hardware work and then onto Server Operating Systems. I progressed again onto a consultancy company based in Reading, UK. Initially working as an engineer performing hardware / software installations for larger companies contracted out to the consultancy company, I moved up into a Consultant position continuing my travel across the UK assisting and providing solutions to companies. I finally moved on again to my current position, working back in Hertfordshire, UK. Again working for a large manufacturing company, this time with over 50,000 users worldwide. I am responsible for the datacenter hardware, the storage environment, the vmware environment and also implementing their new Citrix XenApp farm. My days are busy but also productive, its a friendly environment and in my four years of being with the company, I have seen many changes in technology and infrastructure in use within the company. About the site I started this site as I had been thinking of having more of a presence on the web for a while. On a daily basis, I perform tasks and use tools that others may not use or may not think to do and therefore I thought that I would share some of these experiences and tips with others to help with their day to day work. Currently, my main focus of work is around VMware and Veeam Backup & Replication but hopefully as my tasks progress, I’ll be able to share useful bits of information about other areas of IT as well.

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