[dm-devel] dm-cache module

[Olivier B.]

On 22/03/2010 16:05, Heinz Mauelshagen wrote:
> On Sun, 2010-03-21 at 00:56 -0400, Ming Zhao wrote:
>    
>> Hi Mike,
>>
>> Thank you very much for your advice!
>>
>> I can revise dm-cache code and resubmit it as you suggested. I would
>> also love to know Heinz's progress on his implementation and work with
>> him if there anything I could contribute.
>>      
> Hi all,
>
> this is a list of the functions of my dm-hstore
> device-mapper target implementation:
>
> o caches reads and writes keeping persistent state metadata.
> o writes back in order to enhance streaming performance
>    on fragmented access pattern.
> o can run on top of readonly original device
> o if so, writes back any dirty areas when set readwrite
>    (useful for tests)
> o readonly<->  readwrite access changes supported via message interface
> o initializes metadata for extents in cache in the background
>    in order to fasten cache construction
> o supports cache resizing via message interface or constructor
> o keeps metadata persistent by default
> o stores CRCs with metadata for integrity checks
> o stores versions with metadata to support future metadata migration
>
> Test features only:
> o transient cache
> o cache write through
>
>
> Provides very good performance on SSD cache backing stores.
>
> Has been shelved for a while because of other priorities so I need to
> rebase it to the actual kernel.
>
> Regards,
> Heinz
>
>    
Hi,

Facebook have just released "FlashCache" : 
http://github.com/facebook/flashcache
in the documentation we can read :

Flashcache is built using the Linux Device Mapper (DM), part of the 
Linux Storage Stack infrastructure that facilitates building SW-RAID and 
other components.

So it's an other implementation of the same concept, no ?