RAID will improve the reliability of a system that boots from a hard drive
While I do think that we are all aware of what RAID will do, that is partly my point.
Why 'boot from a hard drive'?
Aside from installation, and booting there are virtually no other performance issues with FreeNAS running from a USB Flash Drive.
Additionally I really do not think it is EVER a good idea to boot any OS from a 'Software RAID Array'...
(My actual point of view is 'it is always a BAD IDEA to boot any OS from a Software RAID Array'...)
Since FeeNAS uses 'Software RAID' for it's Array, that is another reason why I would not choose to do that.
why not put the OS there too if it isn't difficult
I was, precisely responding to one of the posts regarding FreeNAS that said:
getting the actual OS to boot from a raid volume is a bit tricky
Why worry about how 'tricky it is to get FreeNAS' to Boot from a RAID Array when it works quite well Booting from a USB Flash Drive?
Why?
Lastly...
While I have been more geared towards FreeNAS in this discussion much of the following would affect any OS that is used...
For any system you have, recovering from failure should be considered.
Whenever you, including software and hardware, 'touch data on a hard drive' the data to a degree is put in danger...
(Reading, Writing, Deleting, Formatting, Bad Power Rails, Bad SATA Cables, Partially failed Motherboards Parts, etc...)
One of the 'MAIN REASONS' I am a huge proponent of keeping OS and Data separate, is because of recovery.
That way, if/when recovery is necessary due to an OS issue the Data Drives can be offline/physically removed.
Safe...
Not part of the 'fray' so to speak.
It is much better/safer/easier to be able to recover from problems 'in stages'.
Get the OS working...
Validate the Hardware...
Get the Data back online...
Separating Boot/System Storage from Data Storage removes a whole host of potential issues that could affect the Data during a recovery procedure.
An 8GB USB Flash Drive that can be used for FreeNAS is $9...