Boot Drive Question

[NASbox]

Not 100% sure if I'm going to build 9.10 or 11.0, but if it's stable enough, I'll go for 11.0.

I'm looking for recommendations for USB drives to use as a mirrored boot drive,
and these are the choices that I'm looking at: (Canadian Prices from Local Supplier)

SanDisk Ultra Flair 32GB USB 3.0 Flash Drive (SDCZ73-032G-G46) $19.99
SanDisk Ultra Flair 64GB USB 3.0 Flash Drive (SDCZ73-064G-G46) $39.99

SanDisk Extreme 64GB Flash Drive USB 3.0 (SDCZ80-064G-C46) $49.99
SanDisk Extreme 32GB Flash Drive USB 3.0 (SDCZ80-032G-C46) $39.99

A pair of SDCZ73-032G-G46 with tax is about $45 vs $90 for a pair of the
SDCZ80-032G-C46. The Extreme is a lot higher performance than the Ultra
Flair, but I'm wondering is the higher performance worthwhile?

Should I consider a 64GB drive, or is the extra space a waste of money in this
application? I would hope

Are the USB drives accessed after initial boot or is the drive content cached to memory?

Other than configuration changes how often are the boot drives written?

Any comments/guidance is much appreciated.

 

[Stux]

If you have spare SATA ports, then use a SATA SSD. Otherwise use a pair of USB drives.

I use a pair of 16GB Sandisk Ultra Fit USB3 drives on all my servers... so far so good. Fairly cheap. Speed is more than sufficient. They're neat and don't stick out, but essentially become hot-swappable since you can install them on the exterior of the server quite easily.

Drives are not specifically cached, but they are cached into the ZFS ARC since the boot volume is ZFS too.

Primary write load on the USBs happens when you perform a system upgrade. You should not have your system dataset on the USBs once you have a pool you can write it too. The system dataset is constantly written to and it will wear out USBs fairly quickly, but its as easy as selecting a new target in the GUI to change it.

You should start with 11.0-U1.

Extra space on the boot drive just means you can keep more previous installs around... 32GB is overkill. 64GB is excessive.

<8GB is used. I can clear a boot environment if I ever need more space. A future FreeNAS version will probably enable automatic boot environment thinning (hence the Keep column)