F20 System Wide Change: SSD cache

[Florian Weimer]

On 07/15/2013 09:25 PM, Conrad Meyer wrote:

> By default, bcache runs a write-through cache -- it only
> caches clean data. If the caching SSD dies, the bcache layer
> can just forward requests to spinning drive. No data is lost.
>
> (Bcache has a writeback mode where data loss is possible. I
> do not recommend this mode.)

What's the benefit of bcache, compared to just sticking more RAM in the 
machine?  That you can get more cache, especially on systems that are 
short on memory sockets?  Or that the cache persits across reboots 
(something that can be tricky because it requires synchronizing writes 
to the cache and the disk)?

-- 
Florian Weimer / Red Hat Product Security Team