On 01/23/2012 10:04 AM, sc...@web.de wrote:
Hello World!
Perhaps a trivial question. Let us suppose, I follow the instructions
of SOFTRAID(4) for bulding a Raid 1 device sd0 from wd1, wd2, wd3.
Let us suppose that I make a ufs file system in sd0. As I see, there
are fdisc and disklabel partitions in each wd disc and in sd0.
Will I later be able to mount wd1 (wd2, wd3) alone? As a Raid1 with
one disk? And if I want to mount it in other operating system
supporting ufs?
as RAID1 with a FAILED disk, you should be -- that's the idea of RAID
(often forgot, of course; people often forget the point isn't to have
RAID, but to recover data).
As for other operating system supporting UFS, that's kinda an
interesting question. Not sure if any other OSs natively read OpenBSD
partitions (same can be said for Solaris, FreeBSD and NetBSD).
While your goal of having an OpenBSD replacement plan is good (you
should always start out a project with, as one of your design goals,
"how do I switch off this product when a better one comes along or this
one becomes unavailable/unmaintained"), I don't think "pulling disk and
extracting data" is what you need to worry about as much as "moving data
to a new platform at a later date". Should the OpenBSD project dissolve
tomorrow, you would still be able to boot an OpenBSD install disk on any
existing hardware, recover your data, and transfer it to a new
machine/platform as desired. Other than that, OpenBSD speaks NFS
natively, and can speak SMB with additions, and SSH for extracting data,
so I don't think that will be a problem.
And a question not about OpenBSD: is this problem solved with Hardware
Raid or do hardware Raid controles add other info to the discs?
The only hw RAID system I am aware of that you can remove a single disk
from a mirror and have it Just Work in a PC with a native connection are
the Accusys and Arco mirroring boxes -- they let you add a mirror to an
existing single drive, or remove a drive from the box and let you use
either of the drives without the Accusys hardware as a stand-alone.
Unfortunately, they seem to be the exception rather than the rule.
This is why it is important to have another identical RAID controller to
extract data from your disk
I have
a dpt PM37755U2B (SmartRaid V Millenium): is this controler supported
by OpenBSD (not mentioned in DPT(4))?
plug it in and find out!
but...if you have only one...don't use it for anything serious (or be
ready to use your backup...)
I want to make a file server with an old computer, just for backups,
but I want portable discs, not to depend too much on hardware and
operating system. Do someone have an Idea what can I do? :)
Skip your HW RAID if you only have one controller -- you will wish you
had listened to me should it fail.
Either use softraid (yes, it ties you to OpenBSD, but only those disks,
not your data), or simply copy to one disk, then from that disk to the
other disk inside your system.
OpenBSD is among the easiest OSs to move its disks from one machine to
another around -- much easier than Windows or Linux, assuming the new
hardware is supported by the version of OpenBSD on your disks (yet
another reason to keep up to date).
Nick.
