[Sheepdog] TODO list

MORITA Kazutaka morita.kazutaka at lab.ntt.co.jp
Tue Aug 9 13:12:09 CEST 2011

At Mon, 8 Aug 2011 14:45:38 -0700 (PDT),
Ski Mountain wrote:
> Is making it so that sheepdog can mix and match different disks sizes on the list of TODO items?  I mean as disks become larger it should be possible to add in larger disks to the cluster with out having to upgrade the whole cluster at the same time. 

Basically, Sheepdog doesn't support different sized disks now.  To
handle those, you need to take a bit complicated approach (e.g. run
multiple sheep daemons on the same physical machine).

> So you have a cluster in the fowling setup.  Machine A has a 500GB disk, and machine B has a 250GB and machine C has a 250GB disk.   With sheep dog set to store 2 copy's of everyting, everyting would fit on macine A, but machine A and B would split the storage work.  

To determine where to store objects, Sheepdog uses a probabilistic
approach (a consistent hashing algorithm), so we cannot use disk
spaces ideally as you say.  Even if you run two daemons on the machine
A, some objects could be replicated to the machine B and C.

> Also would it be possible to remove the requirement to have local disk to the TODO list?

To remove it, we need to support a failover of connection from VMs to
sheep daemons.



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