Re: Can we trust fsync?

On Fri, Nov 22, 2013 at 1:16 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>> The original mail was referencing a problem with syncing *meta* data
>> though. The semantics around meta data syncs are much less clearly
>> specified, in part because file systems traditionally made nearly all meta
>> data operations synchronous. Doing plug-pull testing on Postgres would not
>> test meta data syncing very well since Postgres specifically avoids doing
>> much meta data operations by overwriting existing files and blocks as much
>> as possible.
>
> True. You're better off with a specialized testing program. (Though
> now you mention it, I wonder whether that program was stressing metadata
> or not.)

You can always stress metadata by leaving atime updates in their full
setting (whatever it is for that filesystem).