[sheepdog] [PATCH 0/2] add cache options 'page' and 'unsafe'

[Liu Yuan]

On 10/22/2012 09:00 PM, MORITA Kazutaka wrote:
> At Mon, 22 Oct 2012 20:35:05 +0800, 迪八哥 wrote:
>> From a user's view,I have totally confused about how many kinks of
>> caches are there in sheepdog and how many configurations can be
>> used for cache...
> 
> The documentation is available at 
> https://github.com/collie/sheepdog/wiki/Backend-Stores%2C-Object-Cache-and-Disk-Cache
>
> 
>> We are exploring Ceph now, and it shows a better performance over
>> sheepdog especially for sequential R/W and random write.I think the
>> Sheepdog and Ceph share a similar internal design(i.e split the
>> image to 4M object, some kinds of consistent-hash has been
>> used).What we think most important is **journal disk** in storage
>> node,Ceph's performance boost up to  3X when an extra 7200rpm sata
>> disk was used for journal.Will sheepdog consider some similar
>> mechanism?
> 
> There is no plan for it yet.  But I know that there is much room for 
> performance improvement, and I'll try any approach for it including 
> something like journaling.
> 

I am going to take a look at journal device mechanism to boost write
performance. For a quick thought, sequential writing journal ahead will
boost CREATE_AND_WRITE operation.

Thanks,
Yuan