Don Armstrong <d...@debian.org> writes: > On Tue, 07 Oct 2014, lee wrote: >> Don Armstrong <d...@debian.org> writes: >> > Doesn't matter. It just has to be a block device that you can add as >> > a physical volume to the volume group. >> >> Isn't a logical volume of a volume group "just" a block device? The >> VMs have their LVs as block devices just fine. > > Sure.
Ok, so I could abuse the swap partition for this. How would I remove the swap partition from the VG once I've made and backed up the snapshots? >> > This is actually one of the many reasons why lvm is awesome. You can >> > migrate whole servers from one set of drives to another with no >> > downtime by using vgextend/pvmove/vgreduce. >> >> Provided that you have free space on your disks? > > You're swapping drives, so presumably one whole set of drives is empty. Well, who can afford that? Someone who can doesn't need to swap drives. >> Besides the swap partition, the only block device I have available is >> a LVM logical volume which belongs to a different VG than the VG I >> want to backup LVs of. >> >> The logical path would be to add the free LV from the other VG to the >> VG that has LVs which I want to make snapshots of in order to back >> them up because that's the only available block device. > > On Tue, 07 Oct 2014, lee wrote: >> Can I merge multiple volume groups into one? > > Yes, using vgmerge, assuming one of the VG is inactivated. Ok, I could do that. And apparently I could split the VG once I'm done. How do I merge VGs that have different extent sizes? VG Name vg_mydata PE Size 256.00 MiB VG Name vg_guests PE Size 16.00 MiB >> The VG is like this: > > [...] > > Lets back up here. What is the output of sudo pvs; sudo lvs; sudo vgs; ? root@heimdall:~# pvs PV VG Fmt Attr PSize PFree /dev/sda3 vg_guests lvm2 a-- 36.25g 0 /dev/sdb vg_mydata lvm2 a-- 3.64t 84.00g root@heimdall:~# lvs LV VG Attr LSize Pool Origin Data% Move Log Copy% Convert lv_acheron vg_guests -wi-ao-- 10.00g lv_charon vg_guests -wi-ao-- 6.00g lv_gulltop vg_guests -wi-ao-- 10.25g lv_jarl vg_guests -wi-ao-- 4.00g lv_jupiter vg_guests -wi-ao-- 6.00g lv_DATA vg_mydata -wi-ao-- 3.40t lv_opt vg_mydata -wi-ao-- 32.00g lv_squid vg_mydata -wi-ao-- 128.00g root@heimdall:~# vgs VG #PV #LV #SN Attr VSize VFree vg_guests 1 5 0 wz--n- 36.25g 0 vg_mydata 1 3 0 wz--n- 3.64t 84.00g The snapshots are to back up guests in vg_guests. They must go into the free space available in vg_mydata. Other than that, there's a 16GB swap partition (/dev/sda2) currently used by one of the guests. Both sda and sdb are logical RAID volumes. Dom0 is on /dev/sda1. As you can see, it's a very straightforward and logical set up, except for the swap partition which is way too large for dom0 and thus has been re-assigned to a guest that actually requires it. The only problem is LVM which doesn't let me make snapshots. > Do I understand you correctly that you want to snapshot a logical > volume, but currently don't have the space on the volume group that your > logical volume is on? yes >> It's very well possible that this VG doesn't reside on a partition but >> on the device itself. How would I convert that into two partitions >> without losing data? > > Volume groups don't reside on partitions or devices. They encompass > physical volumes which do. Physical volumes do not reside on partitions or devices. They provide them. > You can't change the underlying partitioning scheme under a physical > volume which is in use, but if you have enough space, you can migrate > things out to make a phsyical volume unused. /dev/sdb is not partitioned. There was no need to do that. 84GB is free, which is plenty for the snapshots, so it's perfect. -- Hallowed are the Debians! -- 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/87ppdztles....@yun.yagibdah.de