Re: mdadm usage
On Wed, Dec 30, 2020 at 11:42:37AM +0100, Thomas A. Anderson wrote:
> When i enter mdadm --examine /dev/sdb
>
> I get:
>
> /dev/sdb:
>
> MBR Magic: aa55
>
> Partition[0] : 3907026944 sectors at 2048 (type 83)
It would say more than that if sdb had ever been an md RAID member.
Are you sure it was sdb? Could it have been a partition on sdb?
"fdisk -l /dev/sdb" to list partitions. Also be really careful that
sdb really is the device you think it is!
> If hardware raid (like if I bought a controller), would it be any
> different, if I removed the drives and just put on one another machine
> -- would I be able to see the data on it like a normal drive? Or would I
> run into the same issue??
You would run into the same issue but it would be worse because the
other computer would have to have the same brand (possibly even the
exact same model) of hardware RAID. Every RAID system has to put
metadata onto the devices.
With mdadm, the structure on disk is public information. If you run
into difficulty you can get help from a wide pool of people. I have
seen data brought back from some truly disastrous situations in
threads on the linux-raid mailing list (where mostly md-related
things are discussed).
Try the same thing with hardware RAID and your only port of call is
the manufacturer's support desk because the layout of your data is
now proprietary information. For most of us the support desks of
such vendors don't work out well.
In many cases hardware RAID performs better, especially if you get
one with a supercap-backed write cache, but the trend these days is
to do Just a Bunch of Disks (JBOD) with software RAID, btrfs or
zfs.
Cheers,
Andy
--
https://bitfolk.com/ -- No-nonsense VPS hosting
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