Re: Data Deduplication with the help of an online filesystem check

Thomas Glanzmann
2009-05-04T15:15:18Z

Hello Ric,

> (1) Block level or file level dedup?

what is the difference between the two?

> (2) Inband dedup (during a write) or background dedup?

I think inband dedup is way to intensive on ressources (memory) and also
would kill every performance benchmark. So I think the offline dedup is
the right way to go.

> (3) How reliably can you protect the pool of blocks? How reliably can
> you protect the database that maps hashes to blocks?

You have to lock down the i/o requests for the blocks in question and
compare them byte by byte anyway, just to make sure.

> (4) Can you give users who are somewhat jaded confidence in your
> solution (this is where stats come in very handy!)

For virtual machines you can reduce the used data by 1/3. Of course it
can blow in your face when you don't watch your physical resources
closely.

Thomas