Unexplained NorthScale Server Failure

After over 100 days of uptime, our Northscale server suddenly failed to produce any memcache hits. I was able to access the NorthScale Console, which showed the system as "healthy", though the Analytics section showed "NaN" for all values. After rebooting the machine, the issue was resolved and memcached started producing hits again.

Though the details are light, is this a known issue? Is there anything else I can do to diagnose it?

diag output:

per_node_diag = [{'ns_1@<>',
[{version,
[{os_mon,"2.2.4"},
{kernel,"2.13.4"},
{emoxi,"1.0.3"},
{sasl,"2.1.8"},
{ns_server,"1.0.3"},
{dist_manager,"1.0.3"},
{menelaus,"1.0.3"},
{stdlib,"1.16.4"}]},
{config,
{config,
{full,"/etc/opt/NorthScale/1.0.3/config",undefined,
ns_config_default},
[[{port_servers,
[{'_ver',{0,0,0}},
{memcached,"/opt/NorthScale/1.0.3/lib/memcached",
["-E","/opt/NorthScale/1.0.3/lib/bucket_engine.so",
"-e",

"admin=_admin;engine=/opt/NorthScale/1.0.3/lib/default_engine.so;default_bucket_name

=default;auto_create=true",
"-p","11211","-B","auto","-m","15000"],
[{env,
[{"MEMCACHED_CHECK_STDIN","thread"},
{"MEMCACHED_TOP_KEYS","100"},
{"ISASL_PWFILE",
"/etc/opt/NorthScale/1.0.3/isasl.pw"},
{"ISASL_DB_CHECK_TIME","1"}]},
{cd,"."}]}]},
{directory,"/etc/opt/NorthScale/1.0.3"},
{isasl,
[{'_ver',{0,0,0}},
{path,"/etc/opt/NorthScale/1.0.3/isasl.pw"}]}],
[{directory,
"/opt/NorthScale/1.0.3/bin/ns_server/config"},
{rest,[{'_ver',{0,0,0}},{port,8080}]},
{rest_creds,[{'_ver',{0,0,0}},{creds,[]}]},
{isasl,[{'_ver',{0,0,0}},{path,"./priv/isasl.pw"}]},
{bucket_admin,
[{'_ver',{0,0,0}},{user,"_admin"},{pass,"_admin"}]},
{port_servers,
[{'_ver',{0,0,0}},
{memcached,"./priv/memcached",
["-p","11211","-E","./engines/bucket_engine.so",
"-e",

"admin=_admin;engine=./priv/engines/default_engine.so;default_bucket_name=default;au

to_create=false",
"-B","auto"],
[{env,
[{"MEMCACHED_CHECK_STDIN","thread"},
{"MEMCACHED_TOP_KEYS","100"},
{"ISASL_PWFILE","./priv/isasl.pw"},
{"ISASL_DB_CHECK_TIME","1"}]}]}]},
{alerts,
[{'_ver',{0,0,0}},
{email,[]},
{email_alerts,false},
{email_server,
[{user,undefined},
{pass,undefined},
{addr,undefined},
{port,undefined},
{encrypt,false}]},
{alerts,
[server_down,server_unresponsive,server_up,
server_joined,server_left,bucket_created,
bucket_deleted,bucket_auth_failed]}]},
{pools,
[{'_ver',{0,0,0}},
{"default",
[{port,11212},
{buckets,
[{"default",
[{auth_plain,undefined},
{size_per_node,64}]}]}]}]},
{nodes_wanted,['ns_1@<>']}]],
[[{otp,
[{'_ver',{1285,252651,6348}},
{cookie,occajlbqpnurbkcj}]},
{rest,[{'_ver',{1285,255903,898436}},{port,8080}]},
{rest_creds,
[{'_ver',{1285,255903,898636}},
{creds,[{"<>",[{password,'filtered-out'}]}]}]},
{port_servers,
[{'_ver',{0,0,0}},
{memcached,"/opt/NorthScale/1.0.3/lib/memcached",
["-E","/opt/NorthScale/1.0.3/lib/bucket_engine.so",
"-e",

"admin=_admin;engine=/opt/NorthScale/1.0.3/lib/default_engine.so;default_bucket_name

=default;auto_create=true",
"-p","11211","-B","auto"],
[{env,
[{"MEMCACHED_CHECK_STDIN","thread"},
{"MEMCACHED_TOP_KEYS","100"},
{"ISASL_PWFILE",
"/etc/opt/NorthScale/1.0.3/isasl.pw"},
{"ISASL_DB_CHECK_TIME","1"}]},
{cd,"."}]}]},
{alerts,
[{'_ver',{0,0,0}},
{email,[]},
{email_alerts,false},
{email_server,
[{user,undefined},
{pass,undefined},
{addr,undefined},
{port,undefined},
{encrypt,false}]},
{alerts,
[server_down,server_unresponsive,server_up,
server_joined,server_left,bucket_created,
bucket_deleted,bucket_auth_failed]}]},
{pools,
[{'_ver',{1285,274007,38510}},
{"default",
[{port,11212},
{buckets,
[{"default",
[{auth_plain,{"default","default"}},
{size_per_node,12000}]}]}]}]},
{nodes_wanted,['ns_1@<>']}]],
ns_config_default}},
{basic_info,
[{version,
[{os_mon,"2.2.4"},
{kernel,"2.13.4"},
{emoxi,"1.0.3"},
{sasl,"2.1.8"},
{ns_server,"1.0.3"},
{dist_manager,"1.0.3"},
{menelaus,"1.0.3"},
{stdlib,"1.16.4"}]},
{system_arch,"x86_64-unknown-linux-gnu"},
{wall_clock,8837917},
{memory_data,
{18357985280,9145479168,{<0.68.0>,972344}}}]},
{memory,{18357985280,9145479168,{<0.68.0>,972344}}},
{disk,[{"/",10321208,28},{"/mnt",423135208,1}]}]}]

nodes_info = [{struct,[{hostname,<<"<>">>},
{status,<<"healthy">>},
{uptime,<<"8837916">>},
{version,<<"1.0.3">>},
{os,<<"x86_64-unknown-linux-gnu">>},
{memoryTotal,18357985280},
{memoryFree,9212506112},
{mcdMemoryReserved,12000},
{mcdMemoryAllocated,0},
{ports,{struct,[{proxy,11212},{direct,11211}]}},
{otpNode,<<"ns_1@<>">>},
{otpCookie,<<"occajlbqpnurbkcj">>}]}]

buckets = [{"default",
[{auth_plain,{"default","default"}},{size_per_node,12000}]}]