Help, my disk array has one dead member

[Xen]

Liam Proven schreef op 26-03-2017 14:36:

> Firmware RAID only exists because of Microsoft's licensing policies.
> 
> Windows can create and manage RAID sets of various types just fine. It
> can do RAID 0, 1, 0+1, 10, 5, 6 etc.

Windows cannot include RAID on the boot disk.

If you have sources indicating otherwise, let me know, but Windows RAID 
uses dynamic disks and you cannpot make a dynamic disk of your boot 
device.

I guess I am wrong about it, the Microsoft Dynamic Disks page is a 
morass without much clear information. It was said that Windows 7 cannot 
boot from a dynamic disk with more than 1 volume.

If I converted this disk to dynamic I would lose the Linux partition on 
it ;-). I don't know what would happen to it. There is so much 
unclarity. I guess Linux can read dynamic disks? There is GRUB code that 
handles them.

There is probably no cross-platformness whatsoever regarding the RAID 
part. I wonder if I can create a Windows Dynamic RAID and then turn one 
of the subvolumes into LVM raid.

A Windows Dynamic disks basically no longer has a partition table, 
right.

In other words, I just wonder if I can still have any Linux partitions 
inside a Dynamic Disk.


> But this is considered server functionality and so only the server
> editions of Windows are permitted to do it. Workstation editions will
> only do striping, with concomitant loss of reliability. Presumably the
> logic extends to "so you need to buy a server to keep your stuff on
> safely."

You can't stripe a Windows boot disk, this I know.

"System The system partition or volume contains the hardware-specific 
files needed to load the operating system. The system partition or 
volume can't be part of a striped or spanned volume."

At least this was true for Windows Server 2008. It is hard to find 
updated information.

I am pretty sure I will be able to create e.g. striped sets on Windows 
10 professional.

Here is someone that says:

"An OS cannot be installed on a dynamic disc since it would be 
unbootable on a dynamic disc. I'm afraid that the whole HDD will need to 
be basic. "

But this was about dual booting.

See I just think the entire Windows solution is a big mess.

If GRUB can actually read LDM partitions than I'm sure I can boot from 
it in Linux, but can Linux also read those partitions? In other words, 
can I create whatever I like out of a LDM volume and have Windows not 
interfere with it?

Then I could have LVM "RAID" inside of LDM (Dynamic Disk) volumes that I 
will leave unconfigured in Windows. I still wouldn't like it, as it 
seems to be extremely risky from a "reliablity" standpoint ;-).


> So, because the actual software RAID functionality in Windows is
> disabled in workstation editions. PC vendors have re-implemented it in
> the cheapest possible way, in the firmware.

You realize those RocketRAID cards sell for some €100 to €130 euros 
right (or more).

> DO NOT USE FIRMWARE RAID IN LINUX. AT ALL, EVER, UNDER ANY 
> CIRCUMSTANCES.

All of your screaming isn't going to do much good. If it's the only way 
to be cross-platform.

> If you need a software RAID, use Linux software RAID.

Hardware cards as well as firmware BIOS typically have superior user 
interfaces. The AMD software was also exceptionally good, it just bugged 
out in the most important operation. I haven't seen anything from Linux 
that was really friendly; the mdadm interface is worse than what existed 
before; you can't use it witout a cheatsheet telling you what to do.

I am running (well, it is not doing anything) an mdadm Linux system that 
I once installed using the Debian installer that can support these 
configurations. I have NO clue what to do if anything breaks. I would 
have to look it up first.

So ehm. Linux software raid would be awfully nice if it was actually 
usable.

I would try (and I might try) (and I will try) LVM RAID which is almost 
the same as regular mdadm software RAID now.

But LVM is also plagued by stuff that will just break.

Currently the usability balance does not really favour Linux, still.

LVM is just a bitch to work with if you do the more advanced stuff as 
well. They also don't care *too* much about fail-safe operation.