On 2015-09-17 20:34, Duncan wrote:
The other reason, as has been pointed out in a different sub-thread, is that if you have a guaranteed good hardware RAID controller, which has a known good built in non-volatile write cache, and you turn off write-reordering, and you turn off the write-caches on all the connected hard drives, then it is relatively safe. Of course, the chances of most people actually meeting all those conditions is pretty slim.Zygo Blaxell posted on Wed, 16 Sep 2015 18:08:56 -0400 as excerpted:On Wed, Sep 16, 2015 at 03:04:38PM -0400, Vincent Olivier wrote:OK fine. Let it be clearer then (on the Btrfs wiki): nobarrier is an absolute no go. Case closed.Sometimes it is useful to make an ephemeral filesystem, i.e. a btrfs on a dm-crypt device with a random key that is not stored. This configuration intentionally and completely destroys the entire filesystem, and all data on it, in the event of a power failure. It's useful for things like temporary table storage, where ramfs is too small, swap-backed tmpfs is too slow, and/or there is a requirement that the data not be persisted across reboots. In other words, nobarrier is for a little better performance when you already want to _intentionally_ destroy your filesystem on power failure.Very good explanation of why it's useful to have such an otherwise destructive mount option even available in the first place. Thanks! =:^)
Attachment:
smime.p7s
Description: S/MIME Cryptographic Signature
