Re: [Moosefs-users] Balancing of space with differently sized chunk servers

[Steve T. <sm...@cb...>]

On Tue, 27 Mar 2012, Jeff Williams wrote:

> I am happy to be pointed to some documentation, but I was wondering how 
> moosefs balances files between chunk servers with different available 
> space. Our case in point is we have dell servers with MD1200 disk 
> shelves attached. Some are full of 2TB disks, some with 3TB, so some 
> chuck servers will have extra 50% storage.

I haven't seen it documented, but the steady-state behavior in my setup is 
that each chunkserver is populated to the same fill percentage. So it 
seems to me that if you have only two chunkservers, one with n*2 TB and 
one with n*3 TB, and are using a goal of 2, you will never be able to use 
all the space and maintain the goal setting. In this situation, you will 
have to use more than two chunkservers. I have two chunkservers with 8 TB, 
two with 25 TB, and two with 10 TB (second one of these just being built).

Steve