Re: ext3-2.4-0.9.4

[Alan Cox]

> them, and MTAs are portable, they choose chattr +S on Linux. And that's
> a performance problem because it doesn't come for free, but also with
> synchronous data updates, which are unnecessary because there is
> fsync().

chattr +S and atomic updates hitting disk then returning to the app will
give the same performance. You can also fsync() the directory. 

> the "my rename call has returned 0" event. They expect that with the
> call returning the rename operation has completed ultimately, finally,
> for good, definitely and the old file will not reappear after a crash.

Actually the old file re-appearing after the crash is irrelevant. It will
have a previously logged message id. And if you are not doing message id
histories then you have replay races at the SMTP level anyway

> This still implies the drive doesn't lie to the OS about the completion
> of write requests: write cache == off.

Write cache off is not a feature available on many modern disks. You
already lost the battle before you started.

Alan