Viability of using bcache on a 2 raid arrays?

[qaz@lemmy.world]

I was wondering about the possibility of using the following setup with write-caching

btrfs
    bcache
        fast
            mdadm (RAID-1)
                ssd_1
                ssd_2
        slow
            mdadm (RAID-5)
                hdd_1
                hdd_2
                hdd_3
                hdd_4

Is this viable / reasonable? The arch wiki mentions the possibility of data loss when using write-caching when the SSD fails, but shouldn't the SSD RAID array prevent that? It also mentions "bcache and BTRFS could leave you with a corrupted file system" is this still true? The wiki page mentions that it's unclear if this is still an issue.

Someone also left the following comment on the discussions page regarding BTRFS in 2023:

The issues with btrfs + bcache were fixed 10 years ago. The btrfs wiki no longer mentions historic gotchas for kernels older than 4.14. I think we should remove this warning. Any objections?

[just_another_person@lemmy.world]

I'm not sure I'd personally be trusting bcache with anything at all at this point...

[merthyr1831@lemmy.ml]

Does this use Btfs' RAID5? If so you might want to avoid since RAID5/6 arent production ready for Btrfs and contain known bugs that can lead to parity loss.

[qaz@lemmy.world]

No, I'm aware of BTRFS's RAID 5/6 issues, this uses mdadm's RAID.

[slacktoid@lemmy.ml]

I've got a similar setup without the raid bcache cache drive and wish I did that as it should make maintenance easier. I think it should work. Tho I dunno the gotchas for btrfs and have only done it with xfs. Why btrfs if you don't mind me asking?

[qaz@lemmy.world]

I would like to use BTRFS for deduplication and snapshots.

[tiddy@sh.itjust.works]

Any reason you dont just use bcachefs?

Supports various write-cache configurations, and seperate forgrouns/background replications (a la raid 1).

I think its even more stable than raid because it'll auto-balance when a disk fails, but I'm not as certain in that