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Posted to user@cassandra.apache.org by Erik Forsberg <fo...@opera.com> on 2016/04/19 14:24:35 UTC
A few misbehaving nodes
Hi!
I have this problem where 3 of my 84 nodes misbehave with too long GC
times, leading to them being marked as DN.
This happens when I load data to them using CQL from a hadoop job, so
quite a lot of inserts at a time. The CQL loading job is using
TokenAwarePolicy with fallback to DCAwareRoundRobinPolicy. Cassandra
java driver version 2.1.7.1 is in use.
My other observation is that around the time the GC starts to work like
crazy, there is a lot of outbound network traffic from the troublesome
nodes. If a healthy node has around 25 Mbit/s in, 25 Mbit/s out, an
unhealthy sees 25 Mbit/s in, 200 Mbit/s out.
So, something is iffy with these 3 nodes, but I have some trouble
finding out exactly what makes them differ.
This is Cassandra 2.0.13 (yes, old) using vnodes. Keyspace is using
NetworkTopologyStrategy with replication 2, in one datacenter.
One thing I know I'm doing wrong is that I have slightly differing
number of hosts in each of my 6 chassies (One of them have 15 nodes, one
of have 13, the remaining have 14). Could what I'm seeing here be the
effect of that?
Other ideas on what could be wrong? Some kind of vnode imbalance? How
can I diagnose that? What metrics should I be looking at?
Thanks,
\EF
Re: A few misbehaving nodes
Posted by Patrick McFadin <pm...@gmail.com>.
Can you show the output of a tpstats on one of the effected nodes? That
will give some indication where the trouble might be.
Patrick
On Tue, Apr 19, 2016 at 6:54 AM, sai krishnam raju potturi <
pskraju88@gmail.com> wrote:
> hi;
> do we see any hung process like Repairs on those 3 nodes? what does
> "nodetool netstats" show??
>
> thanks
> Sai
>
> On Tue, Apr 19, 2016 at 8:24 AM, Erik Forsberg <fo...@opera.com> wrote:
>
>> Hi!
>>
>> I have this problem where 3 of my 84 nodes misbehave with too long GC
>> times, leading to them being marked as DN.
>>
>> This happens when I load data to them using CQL from a hadoop job, so
>> quite a lot of inserts at a time. The CQL loading job is using
>> TokenAwarePolicy with fallback to DCAwareRoundRobinPolicy. Cassandra java
>> driver version 2.1.7.1 is in use.
>>
>> My other observation is that around the time the GC starts to work like
>> crazy, there is a lot of outbound network traffic from the troublesome
>> nodes. If a healthy node has around 25 Mbit/s in, 25 Mbit/s out, an
>> unhealthy sees 25 Mbit/s in, 200 Mbit/s out.
>>
>> So, something is iffy with these 3 nodes, but I have some trouble finding
>> out exactly what makes them differ.
>>
>> This is Cassandra 2.0.13 (yes, old) using vnodes. Keyspace is using
>> NetworkTopologyStrategy with replication 2, in one datacenter.
>>
>> One thing I know I'm doing wrong is that I have slightly differing number
>> of hosts in each of my 6 chassies (One of them have 15 nodes, one of have
>> 13, the remaining have 14). Could what I'm seeing here be the effect of
>> that?
>>
>> Other ideas on what could be wrong? Some kind of vnode imbalance? How can
>> I diagnose that? What metrics should I be looking at?
>>
>> Thanks,
>> \EF
>>
>>
>>
>
Re: A few misbehaving nodes
Posted by Erik Forsberg <fo...@opera.com>.
On 2016-04-19 15:54, sai krishnam raju potturi wrote:
> hi;
> do we see any hung process like Repairs on those 3 nodes? what
> does "nodetool netstats" show??
No hung process from what I can see.
root@cssa02-06:~# nodetool tpstats
Pool Name Active Pending Completed Blocked
All time blocked
ReadStage 0 0 1530227
0 0
RequestResponseStage 0 0 19230947
0 0
MutationStage 0 0 37059234
0 0
ReadRepairStage 0 0 80178
0 0
ReplicateOnWriteStage 0 0 0
0 0
GossipStage 0 0 43003
0 0
CacheCleanupExecutor 0 0 0
0 0
MigrationStage 0 0 0
0 0
MemoryMeter 0 0 267
0 0
FlushWriter 0 0 202
0 5
ValidationExecutor 0 0 212
0 0
InternalResponseStage 0 0 0
0 0
AntiEntropyStage 0 0 427
0 0
MemtablePostFlusher 0 0 669
0 0
MiscStage 0 0 212
0 0
PendingRangeCalculator 0 0 70
0 0
CompactionExecutor 0 0 1206
0 0
commitlog_archiver 0 0 0
0 0
HintedHandoff 0 1 113
0 0
Message type Dropped
RANGE_SLICE 1
READ_REPAIR 0
PAGED_RANGE 0
BINARY 0
READ 219
MUTATION 3
_TRACE 0
REQUEST_RESPONSE 2
COUNTER_MUTATION 0
root@cssa02-06:~# nodetool netstats
Mode: NORMAL
Not sending any streams.
Read Repair Statistics:
Attempted: 75317
Mismatch (Blocking): 0
Mismatch (Background): 11
Pool Name Active Pending Completed
Commands n/a 1 19248846
Responses n/a 0 19875699
\EF
Re: A few misbehaving nodes
Posted by sai krishnam raju potturi <ps...@gmail.com>.
hi;
do we see any hung process like Repairs on those 3 nodes? what does
"nodetool netstats" show??
thanks
Sai
On Tue, Apr 19, 2016 at 8:24 AM, Erik Forsberg <fo...@opera.com> wrote:
> Hi!
>
> I have this problem where 3 of my 84 nodes misbehave with too long GC
> times, leading to them being marked as DN.
>
> This happens when I load data to them using CQL from a hadoop job, so
> quite a lot of inserts at a time. The CQL loading job is using
> TokenAwarePolicy with fallback to DCAwareRoundRobinPolicy. Cassandra java
> driver version 2.1.7.1 is in use.
>
> My other observation is that around the time the GC starts to work like
> crazy, there is a lot of outbound network traffic from the troublesome
> nodes. If a healthy node has around 25 Mbit/s in, 25 Mbit/s out, an
> unhealthy sees 25 Mbit/s in, 200 Mbit/s out.
>
> So, something is iffy with these 3 nodes, but I have some trouble finding
> out exactly what makes them differ.
>
> This is Cassandra 2.0.13 (yes, old) using vnodes. Keyspace is using
> NetworkTopologyStrategy with replication 2, in one datacenter.
>
> One thing I know I'm doing wrong is that I have slightly differing number
> of hosts in each of my 6 chassies (One of them have 15 nodes, one of have
> 13, the remaining have 14). Could what I'm seeing here be the effect of
> that?
>
> Other ideas on what could be wrong? Some kind of vnode imbalance? How can
> I diagnose that? What metrics should I be looking at?
>
> Thanks,
> \EF
>
>
>