[Lustre-devel] "Simple" HSM straw man

[Eric Barton]

Aurelien,

>  >> I don't think we want to block the write just because the HSM
>  >> copy isn't done yet.  If the data is changing, then the policy
>  >> engine shouldn't have started a copyout process in the first
>  >> place.
>  >
>  > Indeed.
> 
> You were speaking of a FS with only one big file and so we need to
> have a way to be sure it will be copied at least once, even if
> people are writting on it.  In this case, with a classical policy
> engine, this file will never be copied out because data is
> constantly changing.

I'm not so sure that's a realistic case.  If this file is so active
that it's impossible to take a consistent copy of it without some
sort of a snapshot facility, does that really mean it's a candidate
for archiving?

    Cheers,
              Eric