Re: LMDB integrity with MDB_NOSYNC on various filesystems

Dimitrios Apostolou wrote:

Hello,

I'm reading in LMDB docs that MDB_NOSYNC will not allow database corruption under certain conditions:

...

However, if the filesystem preserves write order and the MDB_WRITEMAP flag is not used, transactions exhibit ACI (atomicity, consistency, isolation) properties and only lose D (durability). I.e. database integrity is maintained, but a system crash may undo the final transactions

Do we know if these conditions are valid for modern filesystems like ext3, ext4, XFS and how this is affected by various mount options (e.g. ordered, writeback etc)?

Read up on the specific filesystems you're interested in. These things change too frequently for us to track, and it's your responsibility to know what you're deploying.