Considerations for un-mirrored boot drive

[Tom_]

Hi all,

My system is currently running happily with mirrored 16 GB SanDisk Cruzer Fit 2.0 boot drives. A week or so ago, one of the boot drives failed. No big deal, I had a spare (same size, brand and model) so after determining which one was going south I took it out and plugged the new one in. However, when I tried to replace the failed drive in the FreeNAS GUI, I got the "device too small" error. Also no big deal, I have config backups, so I reinstalled FreeNAS to the two working USB drives, imported the config and was up and running again within an hour or so.

Now I'm thinking that if I will have to re-install FreeNAS if one of my boot drives fails, I would not be a lot worse off using an un-mirrored boot drive. My A1SAi-2750F board only has two working USB ports so this would make one available for my UPS. Currently, my UPS is connected to the serial port, and is about 90% functional, but there are problems with the mge-shut driver and I would like to try usbhid-ups. (As an aside, I would be happy to be proven wrong about the USB ports, but I have tried every combination of BIOS settings in "South Bridge" and I cannot get USB 2 or USB 3 devices connected to the board's USB 3 ports to be recognised in FreeNAS).

My question: is there anything I should be considering about running without a mirrored boot drive? The issue I can see is that my config backups are stored in the FreeNAS zpool, so if the boot drive fails in such a way that I can't boot at all, I won't be able to get to the config backup. My understanding is that this would simply require booting off a fresh install and importing the zpool to access my config backup. Anyway, the configs backups are further backed up to CrashPlan so I could conceivably download them from there with the mobile app and email them to myself!

Be happy to have some feedback if anyone sees any issues.

Thanks very much for reading,

Tom

 

[Robert Smith]

UPSes in general work much more stable via COM port than USB.

This is the first time I have ever hear of anyone having a UPS communication issues via COM port; if it works at all it usually keeps on working with top stability.

 

[Tom_]

Thanks for the reply. There is no problem with communication but some of the parameters (e.g. battery level when shutdown is triggered) don't seem to work. Googling suggests it's a specific problem with the serial port driver (mge-shut). Also, I don't know how accurate this is, but I got the impression from reading a few messages on the NUT list that USB is preferred... maybe there is more development effort for the USB-based drivers?

 

[Robert Smith]

How good of a UPS you have? The less expensive ones low battery indication can be very unreliable, it can be at 80% one moment, and then just cut off power with no warning the very next second.

I personally prefer to trigger the shut down a certain number of minutes from the ONBAT signal. And if the electricity comes back on before that (UPS goes ONLINE), the shutdown is cancelled.

 

[Tom_]

It's an Eaton 5SC. I posted some more details in another thread where I was trying to get help connecting it via USB .

Actually I am trying to make the settings a bit more conservative since I don't need to ride out long outages. I would like to trigger FreeNAS shutdown when the battery is at 50% and leave a nice long time for FreeNAS to shut down (say 5–10 minutes). But with the mge-shut driver it ignores the parameter set with lowbatt (i.e. battery.charge.low).

 

[Robert Smith]

I have just read your other thread. It sounds like you know exactly what you want. Good luck with that. The state of UPS intercommunication could definitely be better; it starts getting flaky once you want to use more advanced options, unfortunately.

As to your original question, I am wondering how easy it would be to use a single boot device, but to turn on ZFS multiple copies, for better bit-rot protection.

Also the way booting functionality has been progressing in the later versions, I am wondering if FreeNAS developers will soon let us dedicate small portions of data disks to boot from, so no separate boot device is needed at all.

 

[Tom_]

Thanks again for the replies. Another option I guess, considering the current USB vs. SSD boot drive thread, would be to get an SSD in there somehow. I suppose I would have to put an M2 adaptor in the PCIe slot (no free SATA ports), I have no clue as to whether that's a good idea or not...

 

[Mr_N]

I don't see much point to mirroring the boot drive, unless uptime is of importance, given the easy of reinstall and loading config from backup.

 

[Darren Myers]

I don't see much point to mirroring the boot drive, unless uptime is of importance, given the easy of reinstall and loading config from backup.

Saves you time trying to to find what config you had, or if you dont have a backup of your config...it'll save you alot of time and misery having to remake all your shares, and network config(s), etc.

 

[Mr_N]

If you don't have a config backup ... shame on you :P

Maybe if your using cheap-ish USB sticks sure but if you get something more solid its prob not worth the cost/using extra sata port :)