**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'
```
{
    if (!allow_renaming)
        throw Exception("Cannot rename Replicated table, because zookeeper_path contains implicit 'database' or 'table' macro. "
                        "We cannot rename path in ZooKeeper, so path may become inconsistent with table name. If you really want to rename table, "
                        "you should edit metadata file first and restart server or reattach the table.", ErrorCodes::NOT_IMPLEMENTED);
}
void StorageReplicatedMergeTree::rename(const String & new_path_to_table_data, const StorageID & new_table_id)
{
    checkTableCanBeRenamed();
    MergeTreeData::rename(new_path_to_table_data, new_table_id);
    
    if (!is_readonly)
    {
        
        
        try
        {
            auto zookeeper = getZooKeeper();
            zookeeper->set(fs::path(replica_path) / "host", getReplicatedMergeTreeAddress().toString());
        }
        catch (Coordination::Exception & e)
        {
            LOG_WARNING(log, "Cannot update the value of 'host' node (replica address) in ZooKeeper: {}", e.displayText());
        }
    }
    
}
bool StorageReplicatedMergeTree::existsNodeCached(const std::string & path) const