**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 table_lock = lockForShare(
            RWLockImpl::NO_QUERY, getSettings()->lock_acquire_timeout_for_background_operations);
    auto zookeeper = getZooKeeper();
    DataPartsVector parts = grabOldParts();
    if (parts.empty())
        return;
    DataPartsVector parts_to_delete_only_from_filesystem;    
    DataPartsVector parts_to_delete_completely;              
    DataPartsVector parts_to_retry_deletion;                 
    DataPartsVector parts_to_remove_from_filesystem;         
    for (const auto & part : parts)
    {