Re: change UUID of RAID devcies

Am 13.09.22 um 14:47 schrieb Pascal Hambourg:

On 13/09/2022 at 14:21, Reindl Harald wrote:

quoted

Am 13.09.22 um 14:03 schrieb Pascal Hambourg:

quoted

On 13/09/2022 at 13:50, Reindl Harald wrote:

quoted

Am 13.09.22 um 13:48 schrieb Pascal Hambourg:

quoted

Legacy boot on GPT has some requirements, but it works

but we are talking about a LIVE-migration/reshape of existing disks 
with no place left for another partition

So what ? Aren't you going to create a GPT partition table on your 
4-TB drives ? Else you won't be able to use the space beyond 2 TiB. (*)
A GPT partition table supports up to 128 partitions by default.

i won't have a choice as it looks like and so the easiest choice would 
be migrate /boot completly to a USB-stick and simply ignore the 
current /boot RAID1 which is just 482M small

I don't see how it is easier. Also, USB sticks are not reliable

relieble enough for /boot and given that i run a HP microserver with the 
whole OS on a USB stick since 2016 to have only the RAID10 data on the 4 
drives....

However you are right that you can get rid of the current /boot array; I 
don't see the need for a separate /boot, its contents could be included 
in the root filesystem.

and the initrd lives where?
chicken / egg

quoted

since finally the new machines in the next step only support UEFI and 
the uefi-system partition can't live on a RAID it would end there over 
time anyways

Software is not natively supported by EFI boot but there are a few 
tricks to set up a redundant EFI boot: create independent EFI partitions 
on each disk, or create a RAID 1 array with metadata 1.0 (at the end of 
the partition) so that the UEFI firmware can see each RAID partition as 
a normal EFI partition with a FAT filesystem.

sounds all not appealing

quoted

so for now my last remaining question is "how would the command look 
for "Then with just two drives you change the raid to raid-1"

I would not convert existing arrays. Rather create new arrays on the new 
disks and copy the data

i want my identical machines to stay as they are with all their UUIDs 
which is the main topic here

it's not funny when you are used to rsync your /etc/fstab over 11 years 
that doing so would lead in a unbootbale system on the other side

in a perfect world new hardware would still support 4 SATA drives and 
UEFI would be able to boot from a RAID1 like BIOS-boot does no matter 
which of the 4 drives are there and the hardware replacement would be 
insert the 4 old disks and power on

all that new crap sucks completly