On 2015-10-05 11:58, Jason McIntyre wrote: > On Mon, Oct 05, 2015 at 11:14:09AM +0200, Ingo Schwarze wrote: >> >>> On Mon, Oct 5, 2015, at 03:53 AM, Mikael wrote: >> >>>> which FS types are available in the disklabel tool? >> >> The list is in the header file /usr/include/sys/disklabel.h, >> static char *fstypenames[] >> >> I don't think this is documented, not even in readlabelfs(3) or >> in disklabel(5). >> > > we're not talking about the list in fstab(5)?
Ah, look! Well, almost. :-) That list includes types like nfs and tmpfs that are not disk-centric partition types, and it deals with file systems (the exception being swap) whereas a partition type in theory can contain any type of data. One example is the RAID type, that in turn contains data that becomes an abstraction of a disk within a disk. Another is that in the bad old days it was common to store for example Oracle and Informix databases on raw partitions. This was done to squeeze every last ounce of performance out of a server by bypassing the operating system's file system layer. It might have improved performance but was a bloody mess to manage, backups being a particular pain in the rear to deal with as I recall. Unfortunately, the kind of misunderstanding we've seen in this thread comes from the terminology being a bit fuzzy. What I just referred to as partition types, and disklabel et al somewhat incorrectly calls file system types (swap is not a file system for example), is also sometimes called slices. Personally, I think it would be a good thing to bring back slices to the vocabulary. That would emphasize the distinction between physical disk partitions as they appear in the PC-centric hardware world and logical partitions/slices that are a subdivision *within* a disk partition. Not all architectures even have the PC notion of MBR/GPT partitioning, but rather use slices directly as the only means to subdivide a disk. Regards, /Benny
