[CentOS] CentOS 7: software RAID 5 array with 4 disks and no spares?

Thu Feb 19 05:39:41 UTC 2015
Chris Murphy <lists at colorremedies.com>

On Wed, Feb 18, 2015 at 9:25 PM, John R Pierce <pierce at hogranch.com> wrote:

> disks -> partition(s) -> mdraid devices -> PVs -> VG -> LV -> file system.
> phew.

You might be a candidate for LVM integrated raid. It uses the md
kernel code on the backend, but it's all LVM tools to create, manage
and monitor. The raid level is defined per LV, instead of all LV's in
a VG inheriting the underlying raid. It supports all levels of raid
including 5/6.

It doesn't quite have all the features of mdadm. But the flexibility
it offers for use cases where LV's are often being created and
destroyed and different redundancy levels/types are desired, it's
neat.

And eventually, one of these years, Btrfs. That is so much simpler to
create and manage.

disk>no partition>Btrfsraid>subvolumes instead of partitions

It doesn't have all the features of mdadm or lvm, especially when it
comes to VM images. But for general purpose data, it's nice. It'll use
different sized drives in a raid56, no fuss, no having to tell it how
to do that. Online addition of yet another (unlike sized) drive and it
just starts using it with a single 'btrfs device add' command. No
restripe/resilver needed.

-- 
Chris Murphy