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From Robert Coli <rc...@eventbrite.com>
Subject Re: General doubts about bootstrap
Date Mon, 08 Jul 2013 21:05:01 GMT
On Sat, Jul 6, 2013 at 1:50 PM, Rodrigo Felix <
rodrigofelixdealmeida@gmail.com> wrote:

>
>    - Is it normal to take about 9 minutes to add a new node? Follows the
>    log generated by a script to add a new node.
>
> Sure.

>
>    - Is there a way to reduce the time to start cassandra?
>
> Not usually.

>
>    - Sometimes cleanup operation takes make minutes (about 10). Is this
>    normal since the amount of data is small (1.7gb at maximum / seed)?
>
> Compaction is throttled, and cleanup is a type of compaction. Bootstrap is
also throttled via the streaming throttle.

>
>    - Considering that I have two seeds in the beginning, their tokens are
>    0 and 85070591730234615865843651857942052864. When I add a new machine, do
>    I need to execute move and cleanup on both seeds? Nowadays, I'm running
>    cleanup on seed 0, move + cleanup on the other seed and neither move nor
>    cleanup on the just added node. Is this OK?
>
> Only nodes which have "lost" ranges need to run cleanup. In general you
should add new nodes "between" other nodes such that "move" is not required
at all.

>
>    - What if I do not run cleanup in any existing node when adding or
>    removing a node? Is the data that was not "cleaned up" still available if I
>    send a scan, for instance, and the scan range is still in the node but it
>    wouldn't be there if I had run cleanup? Data would be gather from other
>    node, ie. the one that properly has the range specified in the scan query?
>
> If data for range [x] is on node [a] but node [a] is no longer considered
an endpoint for range [x], it will never receive a request to serve range
[x].

>
>    - After decommissioning a node, is it advisable to run cleanup in the
>    remaining nodes? The consequences of not to run are the same of not to run
>    when adding a node?
>
> Cleanup is only for the node which lost a range. In decommission case, no
live nodes lost a range, only some nodes gained one.

=Rob

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