On 11/25/2014 09:29 PM, Zygo Blaxell wrote: > On Tue, Nov 25, 2014 at 05:34:15PM +0100, Goffredo Baroncelli wrote: >> On 11/23/2014 01:19 AM, Zygo Blaxell wrote: >> [...] >>> md-raid works as long as you specify the devices, and because it's always >>> the lowest layer it can ignore LVs (snapshot or otherwise). It's also >>> not a particularly common use case, while making an LV snapshot of a >>> filesystem is a typical use case. >> >> I fully agree; but you still consider a *multi-device* btrfs over lvm... >> This is like a dm over lvm... which doesn't make sense at all (as you >> already wrote) > > It makes sense for btrfs because btrfs can productively use LVs on > different PVs (e.g. btrfs-raid1 on two LVs, one on each PV). LVM is > the bottom layer because not everything in the world is btrfs--things > like ephemeral /tmp, boot, swap, and temporary backup copies of the btrfs > (e.g. before running btrfsck) have to live on the same physical drives > as the btrfs filesystems.
Let me to summrize 1) btrfs-single-disk on lvm works fine 2) btrfs-w/multiple-disk on lvm works fine 3) btrfs-single-disk on lvm works fine even with snapshot 4) btrfs-w/multiple-disk doesn't work with lvm AND snapshot However I still doesn't understood why you want btrfs-w/multiple disk over LVM ? > >>>>> and mounting the filesystem fails at 3. >>>> Are you sure ? >>> >>> Yes, I'm sure. I've had to replace filesystems destroyed this way. In a previous email you wrote: >> Multi-device btrfs fails at 2, So I assumed that the point 3 onwards were related to a "single-disk" btrfs. [...] -- gpg @keyserver.linux.it: Goffredo Baroncelli <kreijackATinwind.it> Key fingerprint BBF5 1610 0B64 DAC6 5F7D 17B2 0EDA 9B37 8B82 E0B5 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
