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From "Mohapatra, Kishore" <>
Subject RE: [EXTERNAL] Re: Increasing VNodes
Date Wed, 04 Oct 2017 17:50:44 GMT
Thanks a lot for all of your input. We are actually using Cassandra reaper. But it is just
splitting the ranges into 256 per node.
But I will certainly try out splitting into smaller ranges going thru the system.size_estimate


Kishore Mohapatra
Principal Operations DBA
Seattle, WA
Email :<>

From: Jon Haddad [] On Behalf Of Jon Haddad
Sent: Wednesday, October 04, 2017 10:27 AM
To: user <>
Subject: [EXTERNAL] Re: Increasing VNodes

The site (with the docs) is probably more helpful to learn about how reaper works:<>

On Oct 4, 2017, at 9:54 AM, Chris Lohfink <<>>

Increasing number of tokens will make repairs worse not better. You can just split the sub
ranges into smaller chunks, you dont need to use vnodes to do that. Simple approach is to
iterate through each host token range and split by N and repair them (ie<>)
 To be more efficient you can grab ranges and split based on number of partitions in the range
(ie fetch system.size_estimates and walk that) so you dont split empty or small ranges a ton
unnecessarily, and because not all tables have some fixed N that is efficient.

Using TLPs reaper<>
or DataStax OpsCenter's repair service is easiest solution without a lot of effort. Repairs
are hard.


On Wed, Oct 4, 2017 at 11:48 AM, Jeff Jirsa <<>>
You don't need to change the number of vnodes, you can manually select CONTAINED token subranges
and pass in -st and -et (just try to pick a number > 2^20 that is fully contained by at
least one vnode).

On Wed, Oct 4, 2017 at 9:46 AM, Mohapatra, Kishore <<>>
        We are having a lot of problems in repair process. We use sub range repair. But most
of the time, some ranges fails with streaming error or some other kind of error.
So wondering if it will help if we increase the no. of VNodes from 256 (default) to 512. But
increasing the VNodes will be a lot of efforts, as it involves wiping out the data and bootstrapping.
So is there any other way of splitting the range into small ranges ?

We are using version at the moment.


Kishore Mohapatra
Principal Operations DBA
Seattle, WA
Email :<>

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