"Ann W. Harrison" wrote:

> Nando Dessena wrote:
>>
>> A> If you can shut off updates for the duration of the
>> A> copy, you'll be ok.
>>
>> I wouldn't be sure about that. Perhaps the FS cache might play tricks?
>
> Right - without forced writes, you don't know when the write
> will occur. And of course, even with forced writes, some disk
> controllers add their own caching, which could also cause a
> problem. Backup is a better choice.

It does not matter whether forced writes is on or off in this case.
If another process tries to read opened file with some data
not flushed to disk, then it will get data already present in FS cache,
it will not re-read obsolete data from HD.

Ivan