**Use case**

Currently, `system.replicas` table has `total_replicas` and `active_replicas` columns which are useful to check/alert when some replicas are down. One problem, these columns are numbers. They tell when there is a problem, but you need to further check ZooKeeper or query all the nodes to detect what exact replicas (hosts) are down/inactive/have problems.

**Describe the solution you'd like**

Add a replicas column maybe as a map which would contain the replica name, and it's status. Or, add 2 array columns with `replica_names` and `active_replica_names`

**Alternative**

Something along the line

```sql
select path, value from system.zookeeper where path IN (
    select concat(path, '/', name) from system.zookeeper where path in (select concat(zookeeper_path, '/replicas') from system.replicas)
)
and name = 'is_active'
```
{
    
    fetcher.blocker.cancelForever();
    merger_mutator.merges_blocker.cancelForever();
    parts_mover.moves_blocker.cancelForever();
    restarting_thread.shutdown();
    background_executor.finish();
    part_moves_between_shards_orchestrator.shutdown();
    {
        auto lock = queue.lockQueue();
        
        
        
        queue.pull_log_blocker.cancelForever();
    }
    background_moves_executor.finish();
    auto data_parts_exchange_ptr = std::atomic_exchange(&data_parts_exchange_endpoint, InterserverIOEndpointPtr{});
    if (data_parts_exchange_ptr)
    {
        getContext()->getInterserverIOHandler().removeEndpointIfExists(data_parts_exchange_ptr->getId(replica_path));
        
        data_parts_exchange_ptr->blocker.cancelForever();
        
        std::unique_lock lock(data_parts_exchange_ptr->rwlock);
    }
}
StorageReplicatedMergeTree::~StorageReplicatedMergeTree()