On Sat, Nov 17, 2018 at 01:35:05AM +0100, Willi Rauffer wrote:
> Hello,
>
> we want to make one logical volume out of several physical volumes, but there
> is no \
> LVM (Logical Volume Manager) in OpenBSD!
> Will there be a LVM in OpenBSD in the future?
>
> Thanks...Willi Rauffer, UNOBank.org
There are people on this mailing list infinitely more knowledgeable and
experienced than I both with Linux and BSDs so they will correct me
claims if necessary.
In my experience using LVM2 (LVM is depreciated) to create software RIAD
even on Linux (I have the most experience with RHEL) is a bad idea
unless you belive at the RedHat PR BS. Most people myself included if
they have to use softraid on Linux prefer to do it from mdadm (softraid
discipline for Linux and then perhaps put LVM on the top of it although
I fail to see the purpose). In the lieu of the lack of modern file
system on Linux (Btrfs is a vaporware and ZFS is an external kernel
module which lags many version numbers behind Solaris and FreeBSD) some
PR guys from RedHat started even advertising LVM2 snapshots as a real
snapshots. That is pure BS as they are very expensive operation and for
all practical purposes useless on the legacy file system XFS which is
really the only really stable FS on Linux. If you are storing your data
on Linux you should be using Hardware RAID and XFS.
Not having LVM2 on OpenBSD is a feature not a bug! Dragon Fly BSD has
partial not really functional implementation of LVM that I am quite
familiar with. IIRC NetBSD has LVM2 implementation but it is hard to me
to say usefulness of it as I have never used.
As somebody mentioned. OpenBSD softraid can be used to manage logical
volumes
oko# bioctl softraid0
Volume Status Size Device
softraid0 0 Online 2000396018176 sd3 RAID1
0 Online 2000396018176 0:0.0 noencl <sd0a>
1 Online 2000396018176 0:1.0 noencl <sd1a>
but it is quite crude and it will take you more than a week to rebuild
simple 10 TB mirror. IMHO softraid is far more useful for drive
encryption on your laptop for example than for data storage. I don't
have any experience with Hardware RAID cards on OpenBSD (Areca should
have really good support) which I do prefer over softraid (but not over
ZFS). However OpenBSD lacks modern file system (read HAMMER or HAMMER2)
to take advantage of such set up.
Best,
Predrag
P.S. OpenBSD's NFSv3 server and client implementation is pretty slow so
that begs the question how you are going to access that data pool.
