Thread: ZFS
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Old 17th May 2008
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lvlamb lvlamb is offline
Real Name: Louis V. Lambrecht
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A slice is not exactly a parition.
On Wintel, you have 4 partition, or 3 primary partitions and one "extended" partition chaining logical partitions one to the preceeding one.
A slice in *BSD (and *BSDs habdle this differently) are a "primary" partitions holding several "logical" partitions (called labels).
In one BSD (primary) partition, you house 16 labels. More exactly, 8 OS labels, and 8 "free" hooks to alien labels.
I.e.: the first "alien" label, usually a Windows FAT or NTFS label will be recognized as label "i", the "j", ...
FreeBSD 8 now recognizes 26 labels (as the 26 letters of the alphabet (only limitation), so it can handle non-ufs2/zfs file systems (aka "logical" partitions) from letter "i" to "z" = 18.

So (as "b" is reserved to the swap. "c" descibes the partition volume, "a" is resrved to / root), you can handle 3 partitions with 6 "logical" partitions, plus 18 "logical" partitions.
Reason why these are called slices: 3 slices (holding 6 labels) plus 18 labels.
Or 2 slices (each with 6 labels) and 2 slices each with 18 labels.

Whereas, Wintel only handles "primary" (one partition, one label) and an "extended" partition holding an "unlimited?" number or chaines "logical" partitions.

Clear now?
Clear as mud.
da more I know I know I know nuttin'
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