**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'
```
{
    auto zookeeper = getZooKeeper();
    
    zookeeper->createIfNotExists(zookeeper_path + "/quorum", String());
    zookeeper->createIfNotExists(zookeeper_path + "/quorum/parallel", String());
    zookeeper->createIfNotExists(zookeeper_path + "/quorum/last_part", String());
    zookeeper->createIfNotExists(zookeeper_path + "/quorum/failed_parts", String());
    
    zookeeper->createIfNotExists(replica_path + "/min_unprocessed_insert_time", String());
    zookeeper->createIfNotExists(replica_path + "/max_processed_insert_time", String());
    
    zookeeper->createIfNotExists(zookeeper_path + "/mutations", String());
    zookeeper->createIfNotExists(replica_path + "/mutation_pointer", String());
    
    const auto settings = getSettings();
    if (settings->allow_remote_fs_zero_copy_replication)
    {
        zookeeper->createIfNotExists(zookeeper_path + "/zero_copy_s3", String());
        zookeeper->createIfNotExists(zookeeper_path + "/zero_copy_s3/shared", String());
        zookeeper->createIfNotExists(zookeeper_path + "/zero_copy_hdfs", String());
        zookeeper->createIfNotExists(zookeeper_path + "/zero_copy_hdfs/shared", String());
    }
    
    zookeeper->createIfNotExists(zookeeper_path + "/part_moves_shard", String());
    zookeeper->createIfNotExists(zookeeper_path + "/pinned_part_uuids", getPinnedPartUUIDs()->toString());
    
    zookeeper->createIfNotExists(zookeeper_path + "/alter_partition_version", String());
}
bool StorageReplicatedMergeTree::createTableIfNotExists(const StorageMetadataPtr & metadata_snapshot)