Re: Can a (second) hard disc consist of only 1 extended/logical partition? Or is at least one primary necessary?

Andrew Gideon staggered into the Black Sun and said:
On Tue, 22 Apr 2008 17:47:07 +0000, Dances With Crows wrote:
It's not so much that GRUB *can't* understand LVM, but that LVM is
complex enough that it'd be a complete and total PITA to implement an
LVM reader in real-mode x86 code.
I didn't write "can't"; I wrote "doesn't". Please don't misunderstand
me; what I wrote wasn't a complaint. Given the number of file systems
"out there", it's not unreasonable for GRUB to require /boot be in
some very limited set of file systems

LVM is orthogonal to filesystems. You can have any filesystem you want
inside of an LV. The real problem is that an LV's sectors can be
distributed among a number of PVs, and when you combine that with the
need for the BIOS to be able to read every sector, you end up with a
Real Mess that has no practical solution in the general case.

"It's a hell of a lot easier to resize an LV than it is to resize a
partition" in other words.
True, but the reason is that level of indirection. I think it worthy
to mention that frequently, but I'm one of those "no problem cannot be
solved by another level of indirection" people <grin>.

....except the "too many levels of indirection have caused performance to
suck basketballs through capillary tubes" problem (-: . BTDTGTTS.

If you have your / on an LV, you can hook up a new disk and *move
your / to that disk while the system is running*, which is a pretty
cool thing to be able to do.
Yes? I've never tried this, and I'd have assumed that this wouldn't
work because *something* would have an open descriptor on / thus
preventing the umount of the previous /.

You can't umount / while the system is running. If / is on an LV which
resides on a PV, you can move it using pvmove.

LVM is more complicated, and nothing but Linux can understand LVM
right now. This makes it a bad idea, IMHO, to use LVM unless the box
is only running Linux, or if the other OS(es) will never need to
access the stuff on the LVs.
That's okay; I've yet to be convinced that running anything other than
Linux is a good idea nowadays.

You've never had to deal with brain-damaged suits who think that
I.Exploder is the only browser in existence, and who hard-code
dependence on that into their company's main website? BTDT, though
having a 2K install on virtualbox got around that idiocy.

--
"Assembly of God". Haven't you ever wondered what goes on in a place
like that? What kinds of parts does God need? --Slacquer
My blog and resume: http://crow202.dyndns.org:8080/wordpress/
Matt G|There is no Darkness in Eternity/But only Light too dim for us to see
.

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