nexus oss 3 一直运行得没什么问题，忽然发现运行特别慢然后到服务器去重启，莫名其妙一直启动失败，查看日志发现如下报错信息：

2021-05-24 08:09:50,048+0000 ERROR [FelixStartLevel]  *SYSTEM org.sonatype.nexus.extender.NexusContextListener - Failed to start nexus
com.orientechnologies.orient.core.exception.OStorageException: Cannot open local storage '/nexus-data/db/component' with mode=rw
        DB name="component"
        at com.orientechnologies.orient.core.storage.impl.local.OAbstractPaginatedStorage.open(OAbstractPaginatedStorage.java:323)
        at com.orientechnologies.orient.core.db.document.ODatabaseDocumentTx.open(ODatabaseDocumentTx.java:259)
        at org.sonatype.nexus.orient.DatabaseManagerSupport.connect(DatabaseManagerSupport.java:178)
        at org.sonatype.nexus.orient.DatabaseManagerSupport.createInstance(DatabaseManagerSupport.java:312)
        at java.util.concurrent.ConcurrentHashMap.computeIfAbsent(ConcurrentHashMap.java:1660)
        at org.sonatype.nexus.orient.DatabaseManagerSupport.instance(DatabaseManagerSupport.java:289)
        at java.util.stream.ForEachOps$ForEachOp$OfRef.accept(ForEachOps.java:183)
        at java.util.Spliterators$ArraySpliterator.forEachRemaining(Spliterators.java:948)
        at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:482)
        at java.util.stream.ForEachOps$ForEachTask.compute(ForEachOps.java:290)
        at java.util.concurrent.CountedCompleter.exec(CountedCompleter.java:731)
        at java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:289)
        at java.util.concurrent.ForkJoinTask.doInvoke(ForkJoinTask.java:401)
        at java.util.concurrent.ForkJoinTask.invoke(ForkJoinTask.java:734)
        at java.util.stream.ForEachOps$ForEachOp.evaluateParallel(ForEachOps.java:159)
        at java.util.stream.ForEachOps$ForEachOp$OfRef.evaluateParallel(ForEachOps.java:173)
        at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:233)
        at java.util.stream.ReferencePipeline.forEach(ReferencePipeline.java:485)
        at java.util.stream.ReferencePipeline$Head.forEach(ReferencePipeline.java:650)
        at org.sonatype.nexus.orient.restore.RestoreServiceImpl.doStart(RestoreServiceImpl.java:76)
        at org.sonatype.nexus.common.stateguard.StateGuardLifecycleSupport.start(StateGuardLifecycleSupport.java:67)
        at org.sonatype.nexus.common.stateguard.MethodInvocationAction.run(MethodInvocationAction.java:39)
        at org.sonatype.nexus.common.stateguard.StateGuard$TransitionImpl.run(StateGuard.java:193)
        at org.sonatype.nexus.common.stateguard.TransitionsInterceptor.invoke(TransitionsInterceptor.java:56)
        at org.sonatype.nexus.extender.NexusLifecycleManager.startComponent(NexusLifecycleManager.java:199)
        at org.sonatype.nexus.extender.NexusLifecycleManager.to(NexusLifecycleManager.java:111)
        at org.sonatype.nexus.extender.NexusContextListener.moveToPhase(NexusContextListener.java:304)
        at org.sonatype.nexus.extender.NexusContextListener.frameworkEvent(NexusContextListener.java:201)
        at org.apache.felix.framework.Felix.setActiveStartLevel(Felix.java:1429)
        at org.apache.felix.framework.FrameworkStartLevelImpl.run(FrameworkStartLevelImpl.java:308)
        at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.NullPointerException: null
        at com.orientechnologies.orient.core.storage.impl.local.paginated.wal.ODiskWriteAheadLog.cutTill(ODiskWriteAheadLog.java:919)
        at com.orientechnologies.orient.core.storage.impl.local.OAbstractPaginatedStorage.makeFullCheckpoint(OAbstractPaginatedStorage.java:3706)
        at com.orientechnologies.orient.core.storage.impl.local.OAbstractPaginatedStorage.recoverIfNeeded(OAbstractPaginatedStorage.java:3937)
        at com.orientechnologies.orient.core.storage.impl.local.OAbstractPaginatedStorage.open(OAbstractPaginatedStorage.java:288)
        ... 30 common frames omitted

一开始以为是/nexus-data/db/component 的权限问题，但一直以来启动都没有问题，重新设置 777 权限后仍然没有效果。

解决方法

最后在网上找到了解决方法：把 /nexus-data/db/component 下的出现 0字节 的wal文件全部删掉，重新启动即可！!