On Thu, Aug 30, 2018 at 3:13 AM, Pierre Couderc <pierre@xxxxxxxxxx> wrote: > Trying to install a RAID1 on a debian stretch, I made some mistake and got > this, after installing on disk1 and trying to add second disk : > > > root@server:~# fdisk -l > Disk /dev/sda: 1.8 TiB, 2000398934016 bytes, 3907029168 sectors > Units: sectors of 1 * 512 = 512 bytes > Sector size (logical/physical): 512 bytes / 512 bytes > I/O size (minimum/optimal): 512 bytes / 512 bytes > Disklabel type: dos > Disk identifier: 0x2a799300 > > Device Boot Start End Sectors Size Id Type > /dev/sda1 * 2048 3907028991 3907026944 1.8T 83 Linux > > > Disk /dev/sdb: 1.8 TiB, 2000398934016 bytes, 3907029168 sectors > Units: sectors of 1 * 512 = 512 bytes > Sector size (logical/physical): 512 bytes / 512 bytes > I/O size (minimum/optimal): 512 bytes / 512 bytes > Disklabel type: dos > Disk identifier: 0x9770f6fa > > Device Boot Start End Sectors Size Id Type > /dev/sdb1 * 2048 3907029167 3907027120 1.8T 5 Extended Extended partition type is not a problem if you're using GRUB as the bootloader; other bootloaders may not like this. Strictly speaking the type code 0x05 is incorrect, GRUB ignores type code, as does the kernel. GRUB also ignores the active bit (boot flag). > > > And : > > root@server:~# btrfs fi show > Label: none uuid: eed65d24-6501-4991-94bd-6c3baf2af1ed > Total devices 2 FS bytes used 1.10GiB > devid 1 size 1.82TiB used 4.02GiB path /dev/sda1 > devid 2 size 1.00KiB used 0.00B path /dev/sdb1 That's odd; and I know you've moved on from this problem but I would have liked to see the super for /dev/sdb1 and also the installer log for what commands were used for partitioning, including mkfs and device add commands. For what it's worth, 'btrfs dev add' formats the device being added, it does not need to be formatted in advance, and also it resizes the file system properly. > My purpose is a simple RAID1 main fs, with bootable flag on the 2 disks in > prder to start in degraded mode.... Good luck with this. The Btrfs archives are full of various limitations of Btrfs raid1. There is no automatic degraded mount for Btrfs. And if you persistently ask for degraded mount, you run the risk of other problems if there's merely a delayed discovery of one of the devices. Once a Btrfs volume is degraded, it does not automatically resume normal operation just because the formerly missing device becomes available. So... this is flat out not suitable for use cases where you need unattended raid1 degraded boot. -- Chris Murphy
