unable to restore solr backup

hey , i'm unable to restore backup in to collection . i'm getting error like below

http://localhost:8983/solr/admin/collections?action=RESTORE&name=CountryCodes&location=/opt/solr&collection=concodes&numShards=2&replicationFactor=2&async

result:

{ "responseHeader":\{ "status":0, "QTime":2}

, "Operation restore caused exception:":"org.apache.solr.common.SolrException:org.apache.solr.common.SolrException: Solr cloud with available number of nodes:2 is insufficient for restoring a collection with 2 shards, total replicas per shard 6 and maxShardsPerNode -1. Consider increasing maxShardsPerNode value OR number of available nodes.", "exception":{ "msg":"Solr cloud with available number of nodes:2 is insufficient for restoring a collection with 2 shards, total replicas per shard 6 and maxShardsPerNode -1. Consider increasing maxShardsPerNode value OR number of available nodes.", "rspCode":400}, "status":{ "state":"failed", "msg":"found [1000] in failed tasks"}}