Variance in Drive Size Allowance

[k9bm]

I have a friend who is a FreeBSD purist, he insists on using gpart to leave 100MB reserved/unused at the end of every drive in a zfs array to account for possible variances in number of sectors on drives from different manufacturers. He tells me that if I replace a drive with one that is not identical (same part number), there is a possibility the replacement will fail if it is a few sectors too small. So, should I go to a shell and issue the commands to partition off 100MB or so at the end of every drive, just in case? Or is this something that FreeNAS does on its own?

 

[styno]

Your friend is right, and so is FreeNAS by doing this for you.
https://doc.freenas.org/11/system.html?highlight=swap#advanced - swap space entry

 

[SweetAndLow]

I have a friend who is a FreeBSD purist, he insists on using gpart to leave 100MB reserved/unused at the end of every drive in a zfs array to account for possible variances in number of sectors on drives from different manufacturers. He tells me that if I replace a drive with one that is not identical (same part number), there is a possibility the replacement will fail if it is a few sectors too small. So, should I go to a shell and issue the commands to partition off 100MB or so at the end of every drive, just in case? Or is this something that FreeNAS does on its own?

Freenas already does this for you. When using freenas if you have to use the cli because you think you need to change something you are probably wrong and don't need to change it.

 

[danb35]

Your friend is pretty much wrong these days--capacities are pretty much standardized (and yes, I've seen references for this, but a quick Google isn't finding them right now). If you compare a Seagate, a WD, and a HGST 4 TB disk, you'll see that the capacities are identical. But even so, as noted above, FreeNAS already does something comparable.

 

[rs225]

They are standardized, but you don't hear much about it since it occurs inside a membership organization called IDEMA. www.idema.org

ZFS itself has an allowance for size variance also. A few sectors wouldn't matter.

 

[k9bm]

Gotta love FreeNAS! Many thanks for the replies....