On Mon, Apr 20, 2015 at 12:05:17PM +0200, Dark Victorian Spirit wrote: > I hope i can ask a question on top of this one, > what if i have a PV which is configured and in use for a while, > but i found out that i forgot to set the pertition type on LVM. > > Can i still change this without data loss or risk? > And if i don't will i face issues of another kind?
I believe so. Under Linux, partition types are mostly bookkeeping. According to wikipedia, some partition types imply certain access schemes (such as saying that a XENIX root partition (type 02h) should only be accessed using CHS, not LBA), but no such restrictions apply to Linux partitions. The Partition Type doesn't constrain the data stored on the partition - that is, you can put an NTFS filesystem into a "Linux" partition, even though there's a different code for NTFS. To cut a long story short, yes, you should be fine. Nothing's ever entirely risk-free, though so A) "if it ain't broke, don't fix it" and B) backup before you change it :) > > > On Mon, Apr 20, 2015 at 10:33:13AM +0100, Darac Marjal wrote: > > On Mon, Apr 20, 2015 at 09:26:54AM +0200, Petter Adsen wrote: > > > Is it possible to have two VGs on the same PV? > > > > I don't believe so. The VG is the mapping layer in the LVM stack. It > > maps the LVs to the PVs. If you were to share a PV between VGs, then > > you'd need some way to tell the VGs which parts of the PV they can use > > (letting them battle it out and potentially over-commit the PV is not > > really a good idea). The easiest idea is to split the underlying device > > into multiple PVs (e.g. use partitions). > > > > > > > > If so, how can I make a VG with lots of free space smaller? I'm > > > suspecting that the answer to my first question is "no", since this > > > doesn't seem possible from the man pages. > > > > A quick bit of searching suggests the incantation would be: > > * Boot from a rescue/live disc > > * Activate your VG > > * (You say you've got unallocated space in your VG, so resizing > > filesystems/LVs won't be covered) > > * "lvm pvs" should, at this point, indicate some PFree, which is how > > much you can shrink the PV > > * Run "lvm pvresize /dev/whatever --setphysicalvolumesize 50G" > > (Where /dev/whatever is the PV device and 50G is the new size to > > resize to) > > * Finally, resize the PV's partition appropriately. > > > > At this point, you will have a smaller PV and less unallocated space in > > your VG. You can now create another partition, PV that and add it to a > > second VG. > > > > > > > > Petter > > > > > > -- > > > "I'm ionized" > > > "Are you sure?" > > > "I'm positive." > > > > > > > > -- > To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org > with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org > Archive: https://lists.debian.org/20150420100517.ga5...@kernelbug.org >
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