Re: thin provisioned LUN support

Theodore Tso
2008-11-07T18:36:36Z

On Fri, Nov 07, 2008 at 01:09:48PM -0500, Ric Wheeler wrote:
>
> I don't think that trim bugs should be that common - we just have to be
> very careful never to send down a trim for any uncommitted block.
>

The trim code probably deserves a very aggressive unit test to make
sure it works correctly, but yeah, we should be able to control any
trim bugs.

> Simple is always good, but I still think that the coalescing (even basic
> coalescing) will be a critical performance feature.

Will we be able to query the device and find out its TRIM/UNMAP
alignment requirements? There is also a balanace between performance
(at least if the concern is sending too many separate TRIM commands)
and giving the SSD more flexibility in its wear-leveling allocation
decisions by sending TRIM commands sooner rather than later.

- Ted