Boot device

[mattx38]

Hello,
I’m about to build my own NAS.
I ordered a M2 1To disque to use it as cache disk, and I would like to know if a part of this disk could be used as the boot device.
I read that a lot of people use a USB drive to install FreeNas, but I don’t want to waste a 120 Go SSD for a 8 or 16 Go OS.
Thank you for your advices.
Matt

 

[pschatz100]

Using only part of a disk as a boot disk is technically possible, but not supported - and will cause extra work on your part to maintain. Not a good idea.

As for "wasting" space on a 120Gb SSD - certainly you might have been able to find a small 60Gb or 80Gb disk, but small SSD's are cheap enough that it doesn't really matter. Actually, the extra space will make the disk last longer and will simplify TRIM operations because the system will be able to write a lot more data before it has to start reclaiming space using TRIM. The stability you get from using an SSD as your boot device is well worth it.

 

[mattx38]

Ok fine.
Thank you for this clear answer.
I found a 240 Go for 30€

 

[pschatz100]

Ok fine.
Thank you for this clear answer.
I found a 240 Go for 30€

I don't know what a "240 Go" is, but if it is a flash drive, then I would not use it. Flash drives are not reliable for current versions of FreeNAS and TrueNAS. There will be far too much I/O activity for the flash device to maintain reliable operation, and you will have stability problems. Any recommendations for using a flash drive as a boot device are from old posts and they are not relevant anymore.

 

[mattx38]

It is an SSD drive of 240 Go space. Should be fine.

 

[Etorix]

"Go" (gigaoctet) is French for "GB" (gigabyte). All fine here

@mattx38: Please note that using a L2ARC actually consumes RAM. It's generally recommended not to use a L2ARC with less than 64 GB RAM, and to keep L2ARC smaller than about 5*RAM. By this rule of thumb, a 1 TB L2ARC would require at least 200 GB RAM.

 

[mattx38]

Ok thanks for the precision about L2ARC. I didn’t know the needs. I thought a cache disk could just being used as is.
Since then, I’d rather make different disk pools by type of disk and use the fast M2 to write fast, then in a second time, copy from M2 to HDD to store data ?
I want to use my NAS as a longtime storage for photos, private vidéos and pc backups.

 

[Etorix]

Storage for a (single?) home user should not come with much requirements for speed…
Do you care to share your setup?