5 ms·

In my experience, configuring whole disks as software RAID is a world of pain. My experience is that a disk with a single partition is much more reliable when i

In my experience, configuring whole disks as software RAID is a world of pain. My experience is that a disk with a single partition is much more reliable when in an mdadm array. I wonder whether this was because I was also using a bugged EFI mainboard.

tomxor 8y ago
Perhaps, but either way it is not great to hear some UEFI has been designed to be "clever" to the point it's trying to hand hold users by deciding what should be in the superblock of a device without your explicit permission. I can almost forgive it for OS designed for novices but even then they tend to ask permission - however, putting these assumptions into hardware and not even asking permission - that's a broken piece hardware IMO.
- Filligree 8y ago
  GPT has a backup/recovery feature. If the disk was ever a valid GPT disk, then there'll be a copy of the partition table in the final block -- and if that wasn't cleared properly then a functioning UEFI is supposed to restore the primary table from it. The UEFI bios may be following the spec to the letter, here. If so, the takeaway is to always use `wipefs -a`.
  - nh2 8y ago
    The spec actually says that software should prompt for confirmation and report that it performed changes (see elsewhere in this thread). `wipefs -a` is a good recommendation, but perhaps it can delete too much? In my case, I used `sgdisk --zap` to delete specifically the GPT bytes without deleting other data.
creshal 8y ago
The mdadm manpage specifically mentions to use partitions with a special partition type, not whole disks, to prevent various 3rd party software tools from messing with it.
- nh2 8y ago
  Which part of `man mdadm` says that? My `man mdadm` shows: RAID devices are virtual devices created from two or more real block devices. This allows multiple devices (typically disk drives or partitions thereof) to be combined ... "Disk drives or partitions thereof". I couldn't spot the mention you're referring to.

tomxor 8y ago

Perhaps, but either way it is not great to hear some UEFI has been designed to be "clever" to the point it's trying to hand hold users by deciding what should be in the superblock of a device without your explicit permission. I can almost forgive it for OS designed for novices but even then they tend to ask permission - however, putting these assumptions into hardware and not even asking permission - that's a broken piece hardware IMO.

Filligree 8y ago
GPT has a backup/recovery feature. If the disk was ever a valid GPT disk, then there'll be a copy of the partition table in the final block -- and if that wasn't cleared properly then a functioning UEFI is supposed to restore the primary table from it. The UEFI bios may be following the spec to the letter, here. If so, the takeaway is to always use `wipefs -a`.
- nh2 8y ago
  The spec actually says that software should prompt for confirmation and report that it performed changes (see elsewhere in this thread). `wipefs -a` is a good recommendation, but perhaps it can delete too much? In my case, I used `sgdisk --zap` to delete specifically the GPT bytes without deleting other data.

creshal 8y ago

The mdadm manpage specifically mentions to use partitions with a special partition type, not whole disks, to prevent various 3rd party software tools from messing with it.

nh2 8y ago
Which part of `man mdadm` says that? My `man mdadm` shows: RAID devices are virtual devices created from two or more real block devices. This allows multiple devices (typically disk drives or partitions thereof) to be combined ... "Disk drives or partitions thereof". I couldn't spot the mention you're referring to.