Re: ext3 IO latency measurements (was: Linux 2.6.29)

Alan Cox
2009-03-26T19:00:27Z

> And what's the argument for not doing it in the kernel?
>
> The fact is, "atime" by default is just wrong.

It probably was a wrong default - twenty years ago. Actually it may well
have been a wrong default in Unix v6 8)

However
- atime behaviour is SuS required
- there are users with systems out there using atime and dependant on
proper atime

So we can't change the ABI on them any more than we can decide that next
week write() should return short values on writes to disk interrupted by
signals...

Letting distros flip to relatime means new installs and gradual migration
occurs and nobody gets spectacularly blown up when their archiving
system, their usage profiling and disk balancing tools and the like go
wrong.