On Mon, Sep 15, 2025 at 03:41:14PM +0000, H. Hartzer wrote: > This is a little bit frustrating as one usually uses RAID 1 to > improve reliability, not decrease it!
Define "reliability". In simple terms, RAID 1 offers you _some_ protection against a complete disk failure, (traditionally the risk most envisaged was a head crash). If and only if the failure of one drive doesn't take down the whole machine, (or at least other drives in the mirror, as was common on multi-drop parallel SCSI), then you hopefully gain uptime. The example I usually give for this use-case would be media playout at a radio or tv station - you don't want to wait for 3 hours while you restore from a backup, you need that output to continue immediately. However, (most implementations of), RAID 1 _increase_ your risk of silent data corruption, because they read round-robin from all of the disks in the array. If _any one_ of those disks returns bad data as good, then you read bad data in to the OS level. Why are you using RAID in the first place? What are you trying to achieve? Do you actually have a use-case that would benefit from improved anything over what you get with a simple one SSD, using a normal FFS filesystem, and normal backups? I fail to understand why there is such a desire by so many people to over-complicate things such as filesystems that are already, (in the case of FFS), complicated enough. In general, unless one has a specific use-case for RAID, or they are actually testing and developing the RAID code, then leave it out, (and that applies to any OS, not just OpenBSD). Furthermore, there seem to have been a lot of scare stories recently about data loss on FFS, in various scenarios, but hard facts and reproducible steps are much more thin on the ground.
