**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'
```
{
    LOG_INFO(log, "Restoring replica metadata");
    if (!is_readonly || has_metadata_in_zookeeper)
        throw Exception(ErrorCodes::LOGICAL_ERROR, "It's a bug: replica is not readonly");
    if (are_restoring_replica.exchange(true))
        throw Exception(ErrorCodes::CONCURRENT_ACCESS_NOT_SUPPORTED, "Replica restoration in progress");
    auto metadata_snapshot = getInMemoryMetadataPtr();
    const DataPartsVector all_parts = getDataPartsVector(IMergeTreeDataPart::all_part_states);
    Strings active_parts_names;
    
    
    
    for (const auto & part : all_parts)
    {
        if (part->getState() == DataPartState::Committed)
            active_parts_names.push_back(part->name);
        forgetPartAndMoveToDetached(part);
    }
    LOG_INFO(log, "Moved all parts to detached/");
    const bool is_first_replica = createTableIfNotExists(metadata_snapshot);
    LOG_INFO(log, "Created initial ZK nodes, replica is first: {}", is_first_replica);
    if (!is_first_replica)
        createReplica(metadata_snapshot);
    createNewZooKeeperNodes();
    LOG_INFO(log, "Created ZK nodes for table");
    is_readonly = false;
    has_metadata_in_zookeeper = true;
    if (is_first_replica)