**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'
```
}
        }
        PartLog::addNewParts(getContext(), res_parts, watch.elapsed());
    }
    catch (...)
    {
        PartLog::addNewParts(getContext(), res_parts, watch.elapsed(), ExecutionStatus::fromCurrentException());
        throw;
    }
    tryRemovePartsFromZooKeeperWithRetries(parts_to_remove);
    res_parts.clear();
    parts_to_remove.clear();
    cleanup_thread.wakeup();
    return true;
}
void StorageReplicatedMergeTree::executeClonePartFromShard(const LogEntry & entry)
{
    auto zookeeper = getZooKeeper();
    Strings replicas = zookeeper->getChildren(entry.source_shard + "/replicas");
    std::shuffle(replicas.begin(), replicas.end(), thread_local_rng);
    String replica;
    for (const String & candidate : replicas)
    {
        if (zookeeper->exists(entry.source_shard + "/replicas/" + candidate + "/is_active"))
        {
            replica = candidate;
            break;
        }
    }
    if (replica.empty())