Should I partition all of my HDDs?

[chris.shelton]

This article suggests partitioning each disk to have a little 'buffer zone' to counter the problem of replacing with a disk which could differ slightly in size, is this recommended?

Thanks

 

[Bidule0hm]

It's already managed by FreeNAS thanks to the swap space (2 GB are reserved on each drive) ;)

 

[Ericloewe]

In general, do not mess with the disks. FreeNAS will take care of everything that needs taking care of.

 

[Z300M]

In general, do not mess with the disks. FreeNAS will take care of everything that needs taking care of.

This prompts me to ask a question I was thinking of just the other day: What would happen if a disk were replaced by a smaller one -- not just a few MB smaller but, say, a 5TB drive in place of a 6TB one in a vdev of several 6TB ones? Would the vdev still function but with reduced capacity? -- assuming that that reduced capacity is still great enough to hold the existing data. Or would FreeNAS simply refuse to allow such a substitution. (I'm thinking of a [hypothetical] temporary substitution, e.g., if a drive failed and a same-size replacement were not immediately available.)

 

[Bidule0hm]

You can't, ZFS will throw an error and that's all :)

 

[Ericloewe]

This prompts me to ask a question I was thinking of just the other day: What would happen if a disk were replaced by a smaller one -- not just a few MB smaller but, say, a 5TB drive in place of a 6TB one in a vdev of several 6TB ones? Would the vdev still function but with reduced capacity? -- assuming that that reduced capacity is still great enough to hold the existing data. Or would FreeNAS simply refuse to allow such a substitution. (I'm thinking of a [hypothetical] temporary substitution, e.g., if a drive failed and a same-size replacement were not immediately available.)

You can't downsize ZFS pools because that might possibly in some cases maybe hypothetically require moving blocks around. You'd need block pointer rewrite to do that.

 

[rogerh]

It's already managed by FreeNAS thanks to the swap space (2 GB are reserved on each drive) ;)

Has anyone ever replaced a disk in FreeNAS with a slightly smaller disk and demonstrated that this works without manual intervention? The reason I ask is because I have read many times that this could happen, but never read an account of it actually working.

 

[cyberjock]

People have done it. They simply set the swapspace to 0 in the WebGUI, do the disk replacement, then set it back to 2GB.

As long as the size difference is less than 2GB then it "just works".

 

[rogerh]

People have done it. They simply set the swapspace to 0 in the WebGUI, do the disk replacement, then set it back to 2GB.

As long as the size difference is less than 2GB then it "just works".

OK! I assumed that FreeNAS was supposed to adjust the swap partition size to suit. But this is a manual workaround using the existence of the swap space on the original disks. All is clear!