Re: Drives failures in irregular RAID1-Pool

[Andrei Borzenkov <arvidjaar@gmail.com>]

On 28.07.2023 16:59, Stefan Malte Schumacher wrote:
> Hello,
> 
> I recently read something about raidz and truenas, which led to me
> realizing that despite using it for years as my main file storage I
> couldn't answer the same question regarding btrfs. Here it comes:
> 
> I have a pool of harddisks of different sizes using RAID1 for Data and
> Metadata. Can the largest drive fail without causing any data loss? I
> always assumed that the data would be distributed in a way that would
> prevent data loss regardless of the drive size, but now I realize I
> have never experienced this before and should prepare for this
> scenario.
> 

RAID1 should store each data copy on a different drive, which means all 
data on a failed disk must have another copy on some other disk.

> Total devices 6 FS bytes used 27.72TiB
> devid    7 size 9.10TiB used 6.89TiB path /dev/sdb
> devid    8 size 16.37TiB used 14.15TiB path /dev/sdf
> devid    9 size 9.10TiB used 6.90TiB path /dev/sda
> devid   10 size 12.73TiB used 10.53TiB path /dev/sdd
> devid   11 size 12.73TiB used 10.54TiB path /dev/sde
> devid   12 size 9.10TiB used 6.90TiB path /dev/sdc
> 
> Yours sincerely
> Stefan Schumacher