[system test] failed to delete data, cannot locate database file

Create a 6 nodes cluster installed with couchbase server 2.0.0-1808. Consistent view is disable.
Each node has 14 GB RAM and 2 ebs volumes, one for /data and another for /view
Create 2 bucket and load 9 million items to each bucket.
Create a doc for bucket.

When add 2 nodes to cluster, rebalance failed due to one node down (segfault bug MB-6638).
Stop all loads and restart couchbase server on down node
During rebalance, got write commit failed error. Check memcached logs, see the following error

memcached.log.3.txt:Tue Oct 9 00:18:58.901338 UTC 3: Warning: couchstore_open_db failed, name=/data/saslbucket/122.couch.1 option=0 rev=1 retried=2 error=no such file [none]
memcached.log.3.txt:Tue Oct 9 00:18:58.901368 UTC 3: Warning: failed to open database, vbucketId = 122 fileRev = 1 numDocs = 68
memcached.log.3.txt:Tue Oct 9 00:18:58.901378 UTC 3: Warning: commit failed, cannot save CouchDB docs for vbucket = 122 rev = 1
memcached.log.3.txt:Tue Oct 9 00:18:58.904685 UTC 3: Warning: couchstore_open_db failed, name=/data/saslbucket/55.couch.1 option=0 rev=1 retried=2 error=no such file [none]
memcached.log.3.txt:Tue Oct 9 00:18:58.904700 UTC 3: Warning: failed to open database, vbucketId = 55 fileRev = 1 numDocs = 12
memcached.log.3.txt:Tue Oct 9 00:18:58.904708 UTC 3: Warning: commit failed, cannot save CouchDB docs for vbucket = 55 rev = 1
memcached.log.3.txt:Tue Oct 9 00:23:24.492253 UTC 3: Warning: couchstore_open_db failed, name=/data/saslbucket/344.couch.1 option=0 rev=1 retried=2 error=no such file [none]
memcached.log.3.txt:Tue Oct 9 00:23:24.492286 UTC 3: Warning: failed to open database, vbucketId = 344 fileRev = 1 numDocs = 67
memcached.log.3.txt:Tue Oct 9 00:23:24.492295 UTC 3: Warning: commit failed, cannot save CouchDB docs for vbucket = 344 rev = 1

memcached.log.3.txt:Tue Oct 9 00:23:40.153322 UTC 3: Warning: failed to delete data, cannot locate database file /data/saslbucket/499.couch.1
memcached.log.3.txt:Tue Oct 9 00:23:40.153668 UTC 3: Warning: failed to delete data, cannot locate database file /data/saslbucket/499.couch.1

• Database file exists in node

[root@ip-10-248-109-239 logs]# ls /data/saslbucket/ | grep 499
499.couch.1
[root@ip-10-248-109-239 logs]# ls /data/saslbucket/ | grep 122
122.couch.1

Will add collect info later