Routing

Hi Experts

Can anyone define the difference between two commands on JUNOS "request system halt" and "request system power-off"

Thanks

**EDIT:  Oops, I just realized this is in the Routing forum not the SRX forum.  The info here is applicable to the SRX prodcuts, I honestly don't know how it relates to the routing platforms.

For starters, "request system power-off" is only available, I believe, on SRX240 and lower.  The SRX650 does not support power-off, and I don't think the 3k or 5k do either.

When you halt the system, it shuts down the OS and gracefully terminates processes, syncs disks, etc.  It's a holdover term from the Unix roots that Junos is based on.  Halting won't turn the device off per se, it's still "on", but the OS isn't running so it doesn't do anything. Once a system is safely halted, you can remove power.

"request system power-off" on the SRX240 and below will halt, and then actually turn power off.  I'm not real sure why the 650 and up don't support the full power down, but I suspect it has something to do with the more modular architecture of those devices vs. the mostly monolithic architecture of the 240 and below.

I would add to Keith's reply that the behavior seems to be slightly different for every platform. For EX series switches both "request system halt" and "request system power off" bring down all the processes but do not actually power down the box and <enter> will restart for either. Always makes me laugh that my EX4200 still needs to have the plugged pulled when I do a CLI power off.

J series routers work as expected - halt stops the processes and you hit <enter> to restart them power off takes it all the way down.

The SRX branch work like the J series - halt let's you restart. Power off brings the box down -

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@muttbarker wrote:

 

The SRX branch work like the J series - halt let's you restart. Power off brings the box down -

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** except the 650, which is classified as a branch device.  

What you want consistency? 

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@muttbarker wrote:

What you want consistency? 

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Nah, believe me, I've learned that such luxuries aren't part of living in Juniper-land.  

Thanks for the input guys !

Bumping this old thread since I was looking for some info around this and can add a bit more information.

On both EX4200 and EX8200, it behaves as Kevin said.  Both options shut down the system and allow you to press enter from the console to have the system reboot.  On 8200, it is for each individual routing engine.

ON MX960 though, it behaves slightly differently.  Using "halt" goes into the same state as the EX where you can hit enter to have the RE reboot.  If you use "power-off" though, it appears the RE actually powers itself down.  Booting the RE after that requires having someone physically power cycle the chassis.

Note that for both EX8200 and MX960, the line cards do NOT go offline immediatley when the system is halted.  They have to eventually time out before they finally go offline.  That's actually what I'm skimming through the forums for information on 🙂

Cheers!

-Chad