On 06/23/2015 10:54 AM, Marko Vojinovic wrote:
(1) I have no valid usecase for it. I don't remember when was the last
time I needed to resize partitions (probably back when I was trying to
install Windows 95). Disk space is very cheap, and if I really need to
have *that* much data on a single partition, another drive and a few
intelligently placed symlinks are usually enough. Cases where a symlink
cannot do the job are indicative of a bad data structure design, and
LVM is often not a solution, but a patch over a deeper problem
elsewhere. Though I do admit there are some valid usecases for LVM.
Such as:
1) LVM makes MBR and GPT systems more consistent with each other,
reducing the probability of a bug that affects only one.
2) LVM also makes RAID and non-RAID systems more consistent with each
other, reducing the probability of a bug that affects only one.
3) MBR has silly limits on the number of partitions, that don't affect
LVM. Sure, GPT is better, but so long as both are supported, the best
solution is the one that works in both cases.
4) There are lots of situations where you might want to expand a
disk/filesystem on a server or virtual machine. Desktops might do so
less often, but there's no specific reason to put more engineering
effort into making the two different. The best solution is the one that
works in both cases.
5) Snapshots are the only practical way to get consistent backups, and
you should be using them.
6) If you use virtualization, LV-backed VMs are dramatically faster than
file-backed VMs.
LVM has virtually zero cost, so there's no practical benefit to not
using it.
When btrfs comes along and supports flexible volumes, snapshots, and
reliable storage, then it'll make sense to ditch LVM. Until then, LVM
shouldn't even be a question; the answer is yes.
The point of view that LVM isn't needed when a symlink will do is no
more valid than the opposite point of view: that there's no reason to
play stupid games with symlinks when you have the ability to manage volumes.
(2) It is fragile. If you have data on top of LVM spread over an array
of disks, and one disk dies, the data on the whole array goes away.
That's true of every filesystem that doesn't use RAID or something like
it. It's hardly a valid criticism of LVM.
And since hatred is an irrational thing, you need not look any
further than that. ;-)
Well, let's not forget that you are the one who said that you despise
LVM. As long as you recognize that you aren't rational, I suppose we
agree on at least one thing. :)
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