> Does putting the entire system on ZFS mean we can do > away with > slice level partitioning? I found the whole slice > thing confusing, and I > suspect I won't be the only one coming from Linux to > be confused. I see
Slices on x86 can be thought of as somewhat similar in principle to logical partitions within an extended partition, although (a) only Solaris knows about them, and (b) they may well predate extended/logical partitions. Call it a way to get around the 4 fdisk partition limit. AFAIK, Solaris can _access_ logical partitions but not boot from or be installed in them (which causes problems for people who want a many-way multi-boot setup, not to mention lots of whiney "but Linux can do that..." comparisons). The Sun disk label format has (IIRC) a limit of 16 slices on x86, and 8 on SPARC. On x86, it only exists within the Solaris fdisk partition (to define the slices), while on SPARC, slices are top-level things. Again, the disk label format (give or take minor tweaks) is quite old, and changing it is something with a lot of impact on existing users (who won't want to totally reload from bare metal to upgrade). OTOH, I suspect that EFI labels are going to end up being the way to go, since they're flexible enough and may be the most cross-platform thing out there (although I suspect some portable storage devices may need fdisk label support for quite some time to come, on both x86 and SPARC). I presume there's already plenty of strategy and direction on that sort of thing - there are certainly signs of that, given the increasing EFI support - but that it's just not widely known or discussed. > you can put swap on ZFS, but [2] seems to indicate > that ZFS can only > boot from slices (though [1] says "[i]f you use a > whole disk for a > rootpool, you must use a slice notation (e.g. c0d0s0) > so that it is > labeled with an SMI label"--I'm too much of a noob to > follow that). More recently, Solaris knows about EFI labels, and AFAIK, an all-ZFS disk is labelled automatically by ZFS, with an EFI format label. I don't know to what degree x86 or SPARC supports booting from an EFI-labelled disk, but I expect that would require BIOS or OpenBoot support too. Aside from the simplicity of ZFS being able to do the labelling (which may not really apply to installation), and of course that EFI-labelled disks could be portable from x86 to SPARC (for data disks, anyway - don't see a simple solution for a dual x86/SPARC boot setup), I think the other advantage to ZFS owning an entire disk is that (a) it can safely enable the write cache (i.e. without messing up anything else that may not "know" when to flush it to ensure consistency), and (b) it may be able to manage the disk a bit more efficiently that way. -- This message posted from opensolaris.org _______________________________________________ indiana-discuss mailing list [email protected] http://opensolaris.org/mailman/listinfo/indiana-discuss
