Corrupt GPT on ZFS full-disks that shouldn't be using GPT

Quartz quartz at
Mon Jun 29 23:54:25 UTC 2015

> I do recall a change in ZFS behavior to leave a very small amount of
> space unused at the every end of the drive to account for the
> differences in real sizes between various vendors drives that were
> nominally the same size. This only applied if you used the entire
> disk and did not use any partitioning. This was in both the Solaris
> and OpenSolaris versions of ZFS, so it predates the fork of the ZFS
> code.
> I have had no issues using disks of different manufacturers and even
> models within manufacturers

That runs counter to everything I've ever heard or read. Many people on 
all platforms have complained about this issue over the years and tried 
to come up with workarounds, there's no shortage of hits if you search 
for it. Here's a few random examples:

> I will see if I can dig up the documentation on this.

Please do, because if zfs does have this ability buried somewhere I'd 
love to see how and when you can activate it.

>Note that it is
> a very small amount as drives of the same nominal capacity vary very
> little in real capacity.

The second link of the ones I posted above is from a guy with two 1.5TB 
drives that vary by one MB. I'm not sure what you're considering 
"nominal capacity" in this context, but any margin smaller than that is 
probably not useful in practice.

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