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From Mark Reddy <mark.re...@boxever.com>
Subject Re: bootstrapping new nodes on 1.2.12
Date Wed, 30 Jul 2014 13:06:04 GMT
HI Parag,

I see this output my log many times over for 2 nodes.  We have a cron entry
> across all clusters that force a full GC at 2 AM.  node1 is due to Full
> GC that was scheduled (I can disable this).  Node2 was due to a Full GC
> that occurred during our peak operation (these happen occasionally, we’ve
> been working to reduce them).


Firstly, why are you forcing a GC? Do you have sufficient evidence that
Cassandra is not managing the heap in the way in which your application
requires?

Also how are you accomplishing this full GC? Are you removing the node from
the ring, forcing a GC and then adding it back in? Or are you forcing a GC
while it is in the ring?

1)      Will any node leaving the cluster while streaming force us to
> bootsrap all over again?  If so, is this addressed in future versions?


If the node that is leaving the ring is streaming data to  the
bootstrapping node, yes, this will break the streaming session and no further
streams will be started from that node. To my knowledge, there is nothing
in newer / future versions that will prevent this.


2)      We have too much data to migrate to run on non-production hours.
> How do we make it such that full GC’s don’t impact bootstrapping?  Should
> we increase phi_convict_threshold ?


Again I'll need some more information around these manual GC's. But yes,
increasing the phi value would reduce the chance of a node in the ring
being marked down during a heavy gc cycle.


Mark


On Wed, Jul 30, 2014 at 1:41 PM, Parag Patel <ppatel@clearpoolgroup.com>
wrote:

>  Mark,
>
>
>
> I see this output my log many times over for 2 nodes.  We have a cron
> entry across all clusters that force a full GC at 2 AM.  node1 is due to
> Full GC that was scheduled (I can disable this).  Node2 was due to a Full
> GC that occurred during our peak operation (these happen occasionally,
> we’ve been working to reduce them).  Few Questions
>
>
>
> 1)      Will any node leaving the cluster while streaming force us to
> bootsrap all over again?  If so, is this addressed in future versions?
>
> 2)      We have too much data to migrate to run on non-production hours.
> How do we make it such that full GC’s don’t impact bootstrapping?  Should
> we increase phi_convict_threshold ?
>
>
>
> Parag
>
>
>
>
>
> *From:* Mark Reddy [mailto:mark.reddy@boxever.com]
> *Sent:* Wednesday, July 30, 2014 7:58 AM
>
> *To:* user@cassandra.apache.org
> *Subject:* Re: bootstrapping new nodes on 1.2.12
>
>
>
> Thanks for the detailed response.  I checked ‘nodetool netstats’ and I see
> there are pending streams, all of which are stuck at 0%.  I was expecting
> to see at least one output that was more than 0%.  Have you seen this
> before?
>
>
>
> This could indicate that the bootstrap process is hung due to a failed
> streaming session. Can you check your logs for the following line:
>
>
>
> AbstractStreamSession.java (line 110) Stream failed because
> /xxx.xxx.xxx.xxx died or was restarted/removed (streams may still be active
> in background, but further streams won't be started)
>
>
>
> If that is the case you will need to wipe the node and begin the
> bootstrapping process again
>
>
>
>
>
> Mark
>
>
>
>
>
> On Wed, Jul 30, 2014 at 12:03 PM, Parag Patel <ppatel@clearpoolgroup.com>
> wrote:
>
>  Thanks for the detailed response.  I checked ‘nodetool netstats’ and I
> see there are pending streams, all of which are stuck at 0%.  I was
> expecting to see at least one output that was more than 0%.  Have you seen
> this before?
>
>
>
> Side question – does a new node stream from other nodes in any particular
> order?  Perhaps this is a coincidence, but if I were to sort my hostnames
> in alphabetical order, it’s currently streaming from the last 2.
>
>
>
> *From:* Mark Reddy [mailto:mark.reddy@boxever.com]
> *Sent:* Wednesday, July 30, 2014 4:42 AM
> *To:* user@cassandra.apache.org
> *Subject:* Re: bootstrapping new nodes on 1.2.12
>
>
>
> Hi Parag,
>
>
>
> 1)      Would anyone be able to help me interrupt this information from
> OpsCenter?
>
>
>
> At a high level bootstrapping a new node has two phases, streaming and
> secondary index builds. I believe OpsCenter will only report active
> streams, the pending stream will be listed as such in OpsCenter as well. In
> OpsCenter rather than looking at the Data Size check the used space on
> the Storage Capacity pie chart, this will show how much data is on disk but
> not necessarily live on the node yet.
>
>
>
> Personally I would check 'nodetool netstats' to see what streams are
> remaining, this will list all active / pending stream and what files are to
> be streamed, at the moment you might just be streaming some very large
> files and once complete you will see a dramatic increase in data size.
>
>
>
> If streaming is complete and you use secondary indexes, check 'nodetool
> compcationstats' for any secondary index builds that may be taking place.
>
>
>
>
>
> 2)      Is there anything I can do to speed this up?
>
>
>
> If you have the capacity you could
> increase stream_throughput_outbound_megabits_per_sec in your cassandra.yaml
>
>
>
> If you don't have the capacity you could add more nodes to spread the data
> so you stream less in future.
>
>
>
> Finally you could upgrade to 2.0.x as it contains a complete refactor of
> streaming and should make your streaming sessions more robust and
> transparent: https://issues.apache.org/jira/browse/CASSANDRA-5286
>
>
>
>
>
> Mark
>
>
>
> On Wed, Jul 30, 2014 at 3:15 AM, Parag Patel <ppatel@clearpoolgroup.com>
> wrote:
>
>  Hi,
>
>
>
> It’s taking a while to boostrap a 13th node into a 12 node cluster.  The
> average node size is about 1.7TB.  At the beginning of today we were close
> to .9TB on the new node and 12 hours later we’re at 1.1TB.  I figured it
> would have finished by now because when I was looking on OpsCenter, there
> were 2 transfers remaining.  1 was at 0% and the other was at 2%.  I look
> again now and those same nodes haven’t progressed all day.  Instead I see 9
> more transfers (some of which are progressing).
>
>
>
> 1)      Would anyone be able to help me interrupt this information from
> OpsCenter?
>
> 2)      Is there anything I can do to speed this up?
>
>
>
> Thanks,
>
> Parag
>
>
>
>
>
>
>

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