Monthly Archives: July 2014

Manually disable vmreplica state (unable to extend disk)

Just ran into an issue with a VMware VM that was at one time replicated offsite using VMware’s replication tool. For some reason, when the service was decomissioned, (at least) one of our VMs was still marked as a replicated machine. When a VM is marked as active, then it will not be possible to extend the disk drive. In our case it appears that it was also in the middle of a replication, long since abandoned.

To fix, we found this article: StuffThatMightBeUseful

In the article, the author points out that the VM needs to be shut down. Probably better if the VM is down, but in our case we did not have this option and changed the setting on the running VM. Worked and did not crash. yet.

The steps are simple:

  1. Find the VM_ID (number in 1st column): vim-cmd vmsvc/getallvms |grep “name of your VM”
  2. Confirm current state: vim-cmd hbrsvc/vmreplica.getState VM_ID
  3. Fix: vim-cmd hbrsvc/vmreplica.disable VM_ID

Simple Constant Current Driver for a High Power LED

** Schematic diagram corrected and updated **

Update: New post highlighting a ATtiny85 based PWM LED Driver!

In my previous post, I slapped together a quick LED lighting solution for my workbench… but it is truly a hack. What I really want to do is make a simple constant current driver, so the power LEDs can be used in other projects. One of those projects is an LED swimming pool light. It needs to be running at maximum brightness and low cost.

Updated Schematic, correcting op-amp connections

After much digging and testing, I found a simple circuit using a power FET, an OP Amp and 0.5 ohm resistor.

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