Tag: VMWare

Leave a reply

Reclaiming Free Space

I was tasked earlier in the week to reclaim free space from VMs that have been deleted or from snapshots that have been consolidated.

What I discovered was that from vSphere 5.0 to 5.5 had the ability but was disabled by default due to performance issues on the arrays during reclamation.  However, reclamation can still be done manually by issuing the following command

esxcli storage vmfs unmap -l <datastore name>

What is happening here is that when a VM is either deleted, moved due to SvMotion, or snapshots deleted/ consolidated, the VMFS datastore sees that space has been freed up, but not reported back to the array, and still holds on to that space.  So in the vCenter client, you’ll see the amount of free space available to you right away, but you’ll the LUN reporting a different number. I think this is normally not an issue as long as your datastores don’t fill up or if you’re running alerts against the datastores and not the array.

In any case the above command reclaims the space, but depending on how big the LUN is, it can take long time.

For example, to reclaim 50% of free space from a 8TB LUN took about 11 hours.

Good news, VMware had re-implemented the SCSI UNMAP commands in 6.5

Please keep in mind the scsi unmap command needs to be run from the host console.

Leave a reply

MacOS on vSphere ESXi 6.0

I recently installed MacOS High Sierra (10.13) on ESXi 6.0 for a developer I work with.  The steps I used were from a number of sources found on the InterWebs.

First off you need a Mac to download the installer. On the Mac, go to the App Store and and download MacOS.  While that is downloading, you’ll need to run the Unlocker script found at insanelymac.com.  Please read the notes thoroughly, and yes, a reboot of the host is needed.

After the installer is downloaded, you will need to create the ISO. The following steps are all done on the Mac

Mount the installer:
hdiutil attach /Applications/Install\ macOS\ High\ Sierra.app/Contents/SharedSupport/InstallESD.dmg -noverify -nobrowse -mountpoint /Volumes/install_app

Then create a blank ISO
hdiutil create -o /tmp/HighSierra.cdr -size 7316m SPUD -fs HFS+J

Then mount the blank ISO
hdiutil attach /tmp/HighSierra.cdr.dmg -noverify -nobrowse -mountpoint /Volumes/install_build

Then restore the base image to the blank ISO
asr restore -source /Applications/Install\ macOS\ High\ Sierra.app/Contents/SharedSupport/BaseSysyem.dmg -target /Volumes/install_build -noprompt -noverify -erase

copy the install dependencies
cp /tmp/HighSierra.dmg /Volumes/OS\ X\ Base\ System/

unmount installer image
hdiutil detach /Volumes/OS\ X\ Base\ System

convert to iso
hdiutil convert /tmp/sierra.cdr.dmg -format UDTO -o /tmp/HighSierra.iso

rename to iso and place on Desktop
mv /tmp/HighSierra/iso.cdr ~/Desktop/HighSierra.iso

Enjoy on non Apple Hardware!





Leave a reply

Power settings for ESXi hosts

About 2 weeks ago, I noticed in vRealize Operations Manager that one of my VDI hosts was experiencing higher than normal CPU contention. What was more interesting was that 90% of all VMs on that host had high cpu usage.  Moving a VM off the host, brought down CPU utilization, however, any VM moving to that host, started experiencing the same behavior.  After a few searches it turned out that the host’s power setting was set to balanced.  After setting the to Static High Performance Mode, the CPU contention dropped to below threshold and CPU demand on the host dropped as well.

So note to self and to others, when setting up hosts, set the power to high performance.  Luckily for me a reboot was not required.  This may be differ among vendors though.


Week of 9/24


Past 7 Days


You can see above where I made the change.

Leave a reply

Edge Gateway Firewall in vCloud Director

Had an interesting issue with a client today. He had created quite a few edge gateway firewall rules with success. However a few VMs in his VPGs could not get out to the internet.  After much clicking around and testing different settings, it turns out that to allow all outbound traffic, the protocol on the firewall rule needs to be set to ANY and not TCP.

%d bloggers like this: