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https://issues.apache.org/jira/browse/CASSANDRA-13441?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16006613#comment-16006613
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Julius Žaromskis commented on CASSANDRA-13441:
----------------------------------------------

Hi, any workaround for this issue? I've hit this after upgrading from 3.0.9 to 
3.0.13 and doing sstableupgrade. Noticed weird disk write patterns and started 
seeing migration tasks bouncing around. I've only managed to update first of 
the 3 nodes. Migrations tasks have stopped after I've rebooted first node.

{noformat}
Cluster Information:
        Name: cloud.zaromskis.lt cluster
        Snitch: org.apache.cassandra.locator.DynamicEndpointSnitch
        Partitioner: org.apache.cassandra.dht.Murmur3Partitioner
        Schema versions:
                600b7268-d42a-3b72-8706-093b6c8cfaff: [10.240.0.6]
                77a40699-8e9e-35aa-834e-68c32e40a45a: [10.240.0.7, 10.240.0.8]
{noformat}

{noformat}
Datacenter: dc1
===============
Status=Up/Down
|/ State=Normal/Leaving/Joining/Moving
--  Address     Load       Tokens       Owns (effective)  Host ID               
                Rack
UN  10.240.0.6  284.95 GB  256          63.4%             
d0d83d9d-0dec-45cd-9ca9-93515fa131f3  rack1
UN  10.240.0.7  288.53 GB  256          64.1%             
6d9709a0-0e10-46a1-9afa-d106b74ca9e0  rack1
UN  10.240.0.8  326.31 GB  256          72.5%             
5c969700-8bd9-49a4-9772-1284439f8364  rack1
{noformat}

The schema version of first node would not propagate to other nodes. I'm afraid 
further upgrades might create new schema versions? I can't afford to lose any 
data. Any advise?

> Schema version changes for each upgraded node in a rolling upgrade, causing 
> migration storms
> --------------------------------------------------------------------------------------------
>
>                 Key: CASSANDRA-13441
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-13441
>             Project: Cassandra
>          Issue Type: Bug
>          Components: Schema
>            Reporter: Jeff Jirsa
>            Assignee: Jeff Jirsa
>             Fix For: 3.0.14, 3.11.0, 4.0
>
>
> In versions < 3.0, during a rolling upgrade (say 2.0 -> 2.1), the first node 
> to upgrade to 2.1 would add the new tables, setting the new 2.1 version ID, 
> and subsequently upgraded hosts would settle on that version.
> When a 3.0 node upgrades and writes its own new-in-3.0 system tables, it'll 
> write the same tables that exist in the schema with brand new timestamps. As 
> written, this will cause all nodes in the cluster to change schema (to the 
> version with the newest timestamp). On a sufficiently large cluster with a 
> non-trivial schema, this could cause (literally) millions of migration tasks 
> to needlessly bounce across the cluster.



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