Offline Pool

Introduction

With MD-on-SSD, memory is very tight resource, Evicting some not active pools from memory could save us

memory resources in such case.

Interface

• new pool command 'dmg pool offline' could be introduced to offline one pool which will evict any existed pool/container connections and stop pool from system.

1. pool service should be kept?

2. remove memory from TMPFS for this pool.(unlink tmpfs file)

• new pool command 'dmg pool online' could be used to re-activate pool.

• pool online and offline status should be persistent, that means once a pool is “offline”, system restart should not bring back pool to memory.

1. Currently MS store Pool status, new “offline” status might be introduced to manage this?

2. ds_pool_start_all() will try to stall all pools without filtering, pool with “offline” status should

be not started, from engine side, it has no idea about Pool status. engine might poll this from MS?

or we might store pool status in SMD, pool iterating will query SMD.

• to simplify first version, other pool operations eg query/destroy to a offline pool might be denied until pool status become ready.