Should I mirror my USB boot device?

[chris.shelton]

Hi All,

I have been tasked with setting up a NAS at work and I have a question about possibly mirroring the OS.

I will be going with 6 x 2TB WD Red disks set up in raidz2 and will have NAS4Free on a bootable USB stick. Should basically mirror my OS to another USB stick?

Is there any point in this?

Thanks

[raulfg3]

NO.


But you can save your actual config to a safe place.


and do some test to be sure you are ready to go up in case of disaster.

steps:

1 - save your actual config in a safe place.
2 - suthdown your NAS
3 - do a new fresh install on a new USB key and put old working USB key on a safe place.
4 - boot from new USB install and restore your previosly saved config
5 - reboot and test that your NAS are working fine.

now you have a new working USB key (you boot from it) and an old and usable/working USB key in a safe place.
If your NAS fail, you only need to shutdown and replce USB key to boot from original one to work.

[armandh]

if you have the available ports use ide pata or sata industrial grade flash
http://www.logicsupply.com/components/s ... h-modules/
consumer grade USB flash is mostly junk, but good enough for an emergency back up.

stick to the embedded NAS4Free and commercial grade flash [usb or ide] keep it simple and it will serve you well

good flash will have wear leveling and single layer cells. or just buy a small SSD on close out
but everything over 2 GB is wasted

[chris.shelton]

NO.


But you can save your actual config to a safe place.


and do some test to be sure you are ready to go up in case of disaster.

steps:

1 - save your actual config in a safe place.
2 - suthdown your NAS
3 - do a new fresh install on a new USB key and put old working USB key on a safe place.
4 - boot from new USB install and restore your previosly saved config
5 - reboot and test that your NAS are working fine.

now you have a new working USB key (you boot from it) and an old and usable/working USB key in a safe place.
If your NAS fail, you only need to shutdown and replce USB key to boot from original one to work.

Thanks for your response, but can you explain why it's not recommended? Surely if it's simple enough to mirror the OS to another flash module, then you would just do it, to avoid having to shut down the NAS if one fails.

[chris.shelton]

if you have the available ports use ide pata or sata industrial grade flash
http://www.logicsupply.com/components/s ... h-modules/
consumer grade USB flash is mostly junk, but good enough for an emergency back up.

stick to the embedded NAS4Free and commercial grade flash [usb or ide] keep it simple and it will serve you well

good flash will have wear leveling and single layer cells. or just buy a small SSD on close out
but everything over 2 GB is wasted

Thanks for the recommendation, I was going to stick to a standard USB but will look in to industrial grade flash instead. Do you know why it's not recommended to mirror the OS? Surely if it was mirrored, this would avoid a shut down in the unlikely event that one failed.

Thanks

[b0ssman]

in the embedded install the os gets loaded into ram.

if your usb stick failed while the machine was running. nas4free would not be affected.
you could just not save any config changes.

[chris.shelton]

in the embedded install the os gets loaded into ram.

if your usb stick failed while the machine was running. nas4free would not be affected.
you could just not save any config changes.

Okay I see, thanks. So if the bootable media failed, the system would not just shut down straight away. But in order to replace the bootable media, a shutdown and replacement would be necessary. If the boot flash drive was mirrored, then the system would never need to be shut down, correct? It would just start saving config changes to the other one?

I am just trying to structure it in such a way that shutting it down is a very last resort.

[b0ssman]

since the usb device does not get written to once the server is up it should not fail.

also check out the JetFlash 170.
they are slc usb memory sticks and should last even longer.

[armandh]

once the embedded OS is up and running and configuration is stable the boot medium does nothing.
your up time can gain more from an "always on" [double conversion] UPS
100% reliability requires 100% RELIABLE POWER


if the N4F hardware fails you will be down a few moments any way
the only reason I can see to hardware mirror the boot medium is extreme remote location.
or go the high availability route [HAST]

[b0ssman]

you can always get a hardware raid controller and create a hardware raid 0 to boot from.

[raulfg3]

please read: http://www.zfsnas.com/2015/05/20/experi ... -failures/