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Server AC Power Cycle
I recently got asked a question when delivering a class that I thought I would share.
The student asked the following “when remote is it possible to completely drain the flea power on a Rack or Tower server like you can with a modular system via the virtual reseat option in the MX7000 GUI”
The answer depends on the generation of server you have. With a 14G or 15G Dell server, the iDRAC 9 has the ability to perform what is called “a virtual AC cycle”
On those occasions when it’s necessary for an IT admin to reboot a server, whether due to a faulty hardware component or an operating system ‘stuck’ in an unresponsive state, it may be necessary to drain all power to the server. This step is rare but could be the essential means to drain auxiliary power from capacitors to recover a device in a hung state and reboot the physical device’s firmware stack.
If remote you can run the Virtual AC Cycle by using the “Full Power Cycle” option using the iDRAC GUI, Redfish or RACADM
Note, the virtual A/C power cycle is always available and can be performed regardless of the host state; indeed, it may be required if the host operating system is not responding properly, this process applies to rack/tower systems, whereas for modular systems, it’s best to use the “virtual reseat” option
The below example is showing how to do it via the IDRAC GUI
- Configured in BIOS Settings from the iDRAC UI
- Performs a virtual power reseat
- Disconnects power from server for brief timeframe and then reconnects
- Used for lockups or random issues
With the iDRAC, via the GUI – navigate to Configuration > BIOS Settings > Miscellaneous Settings > Power Cycle Request
- Select “Full Power Cycle” and apply. The pending value column will list the new value
- Apply and reboot will create a job that will start the process of rebooting the server
- Once the job reaches 100% the server will reboot
- When the system reboots it will automatically boot into the lifecycle controller
- Once in the Lifecycle Controller It will then run a job to initiate a full power cycle
- Once the job runs the system will reboot and the server will then shut off for a period of about one minute. During this time, the system will perform the AC Power cycle and perform a flea drain, the iDRAC as a result will be unresponsive for a couple of minutes.
After a period of time the server will then power back on again
covid-19
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April 26th, 2023 19:00
Do you know if this is possible thru DeLL OME?
Dell-Emmet
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April 27th, 2023 09:00
In answer to your query, from OME you can remotely initiate a full AC power cycle but only by using racadm CLI
There are two ways of running the remote racadm commands. I’ll demonstrate both but using either method will perform the same operation.
1. Select the system in question from the “All Device” tab, click more actions and RACADM CLI.
2. The Command Line job wizard will appear, enter the following commands and click next
NOTE: -r —Specifies the reboot type. The type can be one of the following:
NOTE: -s —Specifies the start time for the scheduled job in yyyymmddhhmmss format.
TIME_NOW starts the job immediately and will cause the server to immediately reboot and run the job.
3. The following screen will already have selected the target device that your previously selected from the “All Devices” tab. If you want, you can select a group or another server/servers. In the example below I clicked “1 Selected” and it the following screen appears, that allows you to select multiple systems. For example, I’ve selected two. Click “OK”
5. You can decide on the schedule tab if you want to “Run Now” or you can schedule a date and time
6. You can view the details of the job by going to the “Monitor” tab and clicking on view details
7. It will advise if the commands were successful in the bottom left-hand corner of the image
The second way of performing the same action is very similar but, in this scenario, it will only run on the selected system ie you can’t choose multiple servers.
1. Select the system in question from the “All Device” tab and click “View Details”.
2. Click “Remote Command Line”
3. Enter the same command we listed before and click “Send”
4. It will immediately pop up with the results of command and let you know if the commands were successful or not.
Dell-BarryOSullivan
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May 31st, 2023 08:00
thanks for sharing Emmet,
I thought an administrator had to be physically on-site to disconnect cables, I didn't realize the iDRAC had this option, nice tip!