Q: Datastax OpsCenter 5.1 fails to backup 'All Keyspaces' We recently upgraded our company servers (Datastax Enterprise 4.5.3) to DSE 4.6.0. The only problem we face with that is the new Backup Service, in which we are unable to create a backup for "All Keyspaces". Nevertheless, backing up keyspaces one-by-one works like a charm. The error seems to be coming from the datastax-agent(s) installed on the nodes, and I am enclosing as many details as I can recall below.
OpsCenter Event Log:

Backup of all keyspaces failed: Backup of all keyspaces failed for the following destinations: snapshot   
Snapshot of all keyspaces on node < node-IP > failed:
  clojure.lang.Compiler$CompilerException: java.lang.ClassFormatError:
  Invalid method Code length 96939 in class file clojure/core$eval87,
  compiling:(NO_SOURCE_PATH:0:0) (< node-IP >)
Snapshot of all keyspaces on node < node-IP > failed:
  clojure.lang.Compiler$CompilerException: java.lang.ClassFormatError:
  Invalid method Code length 96939 in class file clojure/core$eval87,
  compiling:(NO_SOURCE_PATH:0:0) (< node-IP >)

The above error (snapshot of all keyspaces...) is a little longer, since it comes once for every available node on the cluster, and in the end the "Backup of all keyspaces failed:..." error is presented.
At the same time, all the datastax-agents present the following error message:

 ERROR [qtp1549990111-47] 2015-02-13 18:35:50,887 Unhandled route
 Exception: clojure.lang.Compiler$CompilerException:
 java.lang.ClassFormatError: Invalid method Code length 96939 in class
 file clojure/core$eval87, compiling:(NO_SOURCE_PATH:0:0)
                      Compiler.java:6567 clojure.lang.Compiler.analyzeSeq
                      Compiler.java:6361 clojure.lang.Compiler.analyze
                      Compiler.java:6616 clojure.lang.Compiler.eval
                      Compiler.java:6608 clojure.lang.Compiler.eval
                      Compiler.java:6582 clojure.lang.Compiler.eval
                           core.clj:2852 clojure.core/eval
                           routes.clj:58 opsagent.http.routes/fn
                             core.clj:94 compojure.core/make-route[fn]
                             core.clj:40 compojure.core/if-route[fn]
                             core.clj:25 compojure.core/if-method[fn]
                            core.clj:107 compojure.core/routing[fn]
                           core.clj:2443 clojure.core/some
                            core.clj:107 compojure.core/routing
                         RestFn.java:139 clojure.lang.RestFn.applyTo
                            core.clj:619 clojure.core/apply
                            core.clj:112 compojure.core/routes[fn]
                            Var.java:415 clojure.lang.Var.invoke
                       middleware.clj:93 opsagent.http.middleware/wrap-application-error[fn]
                       middleware.clj:75 opsagent.http.middleware/wrap-content-type[fn]
                      middleware.clj:112 opsagent.http.middleware/wrap-content-error[fn]
                       middleware.clj:31 opsagent.http.middleware/wrap-request-logging[fn]
                       middleware.clj:17 opsagent.http.middleware/wrap-opscenter-id-check[fn]
                      middleware.clj:123 opsagent.http.middleware/wrap-version-header[fn]
                   keyword_params.clj:32 ring.middleware.keyword-params/wrap-keyword-params[fn]
                           params.clj:58 ring.middleware.params/wrap-params[fn]
                            jetty.clj:19 opsagent.http.jetty/proxy-handler[fn]
                        (Unknown Source) opsagent.http.jetty.proxy$org.eclipse.jetty.server.handler.AbstractHandler$0.handle
                 HandlerWrapper.java:111 org.eclipse.jetty.server.handler.HandlerWrapper.handle
                         Server.java:349 org.eclipse.jetty.server.Server.handle
         AbstractHttpConnection.java:452 org.eclipse.jetty.server.AbstractHttpConnection.handleRequest
         AbstractHttpConnection.java:894 org.eclipse.jetty.server.AbstractHttpConnection.content
         AbstractHttpConnection.java:948 org.eclipse.jetty.server.AbstractHttpConnection$RequestHandler.content
                     HttpParser.java:857 org.eclipse.jetty.http.HttpParser.parseNext
                     HttpParser.java:235 org.eclipse.jetty.http.HttpParser.parseAvailable
             AsyncHttpConnection.java:76 org.eclipse.jetty.server.AsyncHttpConnection.handle
          SelectChannelEndPoint.java:609 org.eclipse.jetty.io.nio.SelectChannelEndPoint.handle
           SelectChannelEndPoint.java:45 org.eclipse.jetty.io.nio.SelectChannelEndPoint$1.run
               QueuedThreadPool.java:599 org.eclipse.jetty.util.thread.QueuedThreadPool.runJob
               QueuedThreadPool.java:534 org.eclipse.jetty.util.thread.QueuedThreadPool$3.run
                        (Unknown Source) java.lang.Thread.run Caused by: java.lang.ClassFormatError: Invalid method Code length 96939 in
 class file clojure/core$eval87
                        (Unknown Source) java.lang.ClassLoader.defineClass1
                        (Unknown Source) java.lang.ClassLoader.defineClass
                        (Unknown Source) java.lang.ClassLoader.defineClass
              DynamicClassLoader.java:46 clojure.lang.DynamicClassLoader.defineClass
                      Compiler.java:4663 clojure.lang.Compiler$ObjExpr.getCompiledClass
                      Compiler.java:3819 clojure.lang.Compiler$FnExpr.parse
                      Compiler.java:6558 clojure.lang.Compiler.analyzeSeq

  INFO [qtp1549990111-47] 2015-02-13 18:35:50,888 HTTP: :post
 /ops/take-snapshot {:req-id "c13bb101-2f9e-4880-8b1f-efc178f49b3e"} -
 500

The above applies to a production cluster of 5 nodes in 2 data centers (Datastax defaults, Cassandra/Analytics DCs and DseSimpleSnitch). The analytics DC works with Spark and CFS.
I have tried the same procedure (upgrade path 4.5.3->4.6.0-> Backup all keyspaces) to my local 2-machine cluster (one Cassandra, one Analytics) with a massively smaller dataset and it works like a charm.

A: There's a (known) bug in OpsCenter 5.1 that causes backups to fail in specific scenarios. Unfortunately, looks like you have . The fix will be in OpsCenter 5.1.1 that's to be released soon.
Workaround that you discovered (per-keyspace backup) should work reliably.
