Pete posted on Fri, 18 Mar 2016 18:16:50 +0000 as excerpted: > On 03/18/2016 09:17 AM, Duncan wrote:
>> So btrfs raid1 has data integrity and repair features that aren't >> available on normal raid1, and thus is highly recommended. >> >> But, raid1 /does/ mean two copies of both data and metadata (assuming >> of course you make them both raid1, as I did), and if you simply don't >> have room to do it that way, you don't have room, highly recommended >> tho it may be. > > This looks like a strong recommendation to get a second SSD for the root > partition and go raid1. Are SSDs more flakey that hdd or are you just a > strong believer in the integrity of raid1? As Austin says, I'd generally consider ssds /more/ reliable than hdds, at least as long as you stay away from the OCZs, etc (but then again, there are spinning rust brands and specific models I stay away from, as well), but the failure modes are a bit different so it's not always as simple as that. But I played with raid1 before btrfs and find the additional data integrity features that btrfs raid1 brings even more compelling, so yes, it would indeed be fair to say that I'm a strong booster of btrfs raid1 in particular. =:^) The roadmapped but still to come feature I'm /really/ looking forward to, however, is N-way-mirroring, because btrfs raid1 is currently very specifically two copies, regardless of how many devices there are, and I would really /really/ like to have the choice of three copies, again, not just for device-failure protection, but because with btrfs checksumming and data integrity, if one copy is found to be bad for whatever reason, be it a crash before all copies were written, or a failing device, a simple bad block on an otherwise fine device, or whatever gamma ray block damage or the like, right now that means the other copy BETTER come out checksum-verified, or that data or metadata is toast, and I'd rest far easier if even if one failed, I knew there was still not just the one copy, but a second, to fall back on as well. With N-way-mirroring, of course that could be 4 or more copies as well, but three is closest to my sweet spot balance between cost and extreme reliability, and I'd very much like to have that choice as an option. -- 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 [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
