[Sheepdog] Object node affinity

[Matthew Law]

On Thu, May 10, 2012 11:44 am, Liu Yuan wrote:
> Nope, at least by design, cached objects will always be the freshest
> one. Though those cached objects are supposed to be flushed to the
> cluster storage and would survive the host node crash, but you will
> still be risking yourself to lose those 'updates' that haven't been
> flushed yet in a disaster that the disk never comes back. You can
> analogize object cache with kernel's page cache, and difference is that
> data is cached into local disk instead of memory.

I wonder what the most common read/write ratio is? -if most users have a
read heavy workload (I suspect this is true) then wouldn't ensuring all
writes are flushed to disk as soon as possible (and are only allowed to be
read from cache when this is completed) still offer some advantage?

I can see that would impact heavily on write performance at the cost of
data security, but then I'm not a developer :-)


Thanks,

Matt.