Dirk Diggler posted on Fri, 29 Sep 2017 22:00:28 +0200 as excerpted: > is there any chance to get my device removed? > Scrub literally takes months to complete (SATA 2/3 mix, about 1 minute > per gigabyte) and i'm not sure if that helps. > I guess same with balance. Mabye there is a quicker way. I can do > without some data if it's corrupted. I have a backup, but i want to > avoid to copy all data from scratch!
btrfs device remove uses an implicit balance to move data to other devices, so even if btrfs device remove were to work for you, it'd proceed at the same speed as balance. [tl;dr stop there] Even in the generic (non-btrfs) case, parity-raid is known to be slow for writes and therefore isn't recommended when speed is of any priority above minimum, thus, only for storage where both raw size and some level of device failure recovery is possible, and minimal speed is acceptable. Between that and the btrfs-specific issues btrfs parity-raid had until kernel 4.13, with known bugs (but not the not btrfs-specific write hole) now fixed but with the possibility of unknown issues still lurking, I'd still not consider btrfs parity-raid particularly viable, tho it's no longer entirely blacklisted as it was until those 4.13 fixes. So I'd suggest surrendering the fight and chalking it up to a learning experience, either taking the loss now and switching to something else, say btrfs raid1 on top of dm/mdraid-0 for higher speed or btrfs raid10 if you prefer to stick with a single layer at the sacrifice of speed, or as you write further down a different subthread, just sticking with what you have (since you do have backups) until a device dies and you really don't have an alternative but to eat that "weeks to fix" penalty. Of course if you have the resources, you can do both at once, continuing to operate on the existing setup, while you create an entirely new setup and either initialize it from the backups, or start copying data to it off the still live raid5, presumably at idle priority so as to affect other operations as little as possible. But the resource requirements to keep both the old and the new in operation at once until you can switch over to the new entirely, are high enough it may not be feasible. -- Duncan - List replies preferred. No HTML msgs. "Every nonfree program has a lord, a master -- and if you use the program, he is your master." Richard Stallman -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
