On 09/01/2011 03:20 PM, Louis-David Mitterrand wrote:
On Thu, Sep 01, 2011 at 12:55:08PM -0400, Doug Ledford wrote:
On 09/01/2011 12:33 PM, Louis-David Mitterrand wrote:
On Thu, Sep 01, 2011 at 04:59:13PM +0100, Robin Hill wrote:
On Thu Sep 01, 2011 at 05:47:59PM +0200, Louis-David Mitterrand wrote:
I'm trying to create a raid6 array from 10x3T disks. Since disks> 2T
must use the GPT partion table I used parted to created a single
partition on each drive with the correct GPT partion type.
Now how do I make sure that these partitions have the correct "raid
autodetect" (fd) id? Is it even still needed? I didn't find any way to
set that flag in (g)parted.
It's only needed for kernel auto-assembly (in which case you're also
limited to 0.90 metadata and 2TB drives), so no, there's no need to use
that. 0xDA seems to be the recommended partition type for RAID arrays
nowadays - that should prevent the OS from trying to read them directly.
Auto-assembly and metadata are not related: I regularly use 1.2 metadata
on non-boot partitions and they auto-assemble fine.
They most certainly are related. There is kernel autoassembly, then
there is user space assembly that's done by udev. They are two
different things. The kernel will only autoassemble version 0.9
arrays, any other arrays are assembled by user space either in the
initramfs or later on in the boot cycle. That you don't have to
manually run mdadm -As doesn't mean that the kernel autoassembly is
working on those arrays.
Ah, thanks for clearing that up. I thought that when mdadm was not
involved then is must be the kernel. Didn't realize udev was at work
there.
Well, udev calls mdadm. If the kernel doesn't autoassemble it, then
mdadm is involved at some point. On older systems, rc.sysinit called
mdadm to assemble non-boot arrays, on modern systems, udev calls mdadm.
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