rtroy@sciencetools.com said: > Here's my imperative: Every change to the structure on disk _must_be_ > written to disk that very instant. On-disk structure changes are _the_ > most critical aspect. Caching disk structure is fine, but having > changes in cache that are not yet reflected on disk is, OK, I'll say > it: STUPID. (Note that I'm _only_ talking about the disk structure, > not file data.) With a stale cache, if power is cut or any other > malfeasance occurrs, the entire volume is at risk. FSCK, even if it > works flawlessly every time, is another silly thing: The file system > _should_ provide for knowledge of what files were open at the time, > and a check be made only of them, where that may make sense. (Some > file systems of the past have not needed _any_ fsck type of checking > following system failure, and they have been quite reliable.) I remain > in dumbfounded awe that Unix/Linux has come all this way with such a > fundamentally flawed file system paradigm. I don't entirely agree with what you say. It IS essential that the filesystem on disk structures reflect all the space used by the file AS WRITTEN TO THE DISK, but the latest changes to information about a file are not always required. For example, every time you access a file the time of that event is recorded. In most circumstances here is no great harm if that information is lost, and there's a mount option to not record it at all so as to improve performance. In those cases where data to be written exceed what can be written in a single write (one sector I think, but there may be cases where you can write more than one sector at a time) there exists a window where inconsistent data may written. If it's important to reduce that possibility then you need to install a UPS. To my mind the important point about a UPS is not that it keeps you up over a power outage (though that is important) but that it allows you to do an orderly shutdown. -- Cheers John Summerfield Microsoft's most solid OS: http://www.geocities.com/rcwoolley/ Note: mail delivered to me is deemed to be intended for me, for my disposition. ============================== If you don't like being told you're wrong, be right!
