[CentOS] OT: Caching synchronous writes

Sat Apr 24 20:41:22 UTC 2010
Ross Walker <rswwalker at gmail.com>

On Apr 24, 2010, at 4:34 PM, Les Mikesell <lesmikesell at gmail.com> wrote:

> Ross Walker wrote:
>> On Apr 24, 2010, at 12:43 PM, Les Mikesell <lesmikesell at gmail.com>
>> wrote:
>>
>>> Ross Walker wrote:
>>>> NFS should always be 'sync' if performance isn't good, then your
>>>> storage isn't good.
>>> Why demand sync on remote storage when you typically don't have it
>>> locally?
>>> Programs that need transactional integrity should know when to fsync
>>> () and for
>>> anything else there's not much difference whether you crash before
>>> or after a
>>> write() was issued in terms of it not completing.
>>
>> Yes, but 'async' ignores those fsyncs and returns immediately.
>
> That sounds like a bug in the nfs client code if fsync() doesn't  
> block until all
> of the data is committed to disk.

It's not the client side I'm talking about, but the server side. We  
were talking NFS servers and exporting sync (obey fsyncs) vs async  
(ignore fsyncs).

The client always mounts async, that's not the problem.

-Ross