private int createServerCache() throws IOException {
    cacheRule.createCache();

    DiskRegionProperties diskRegionProps = new DiskRegionProperties();
    diskRegionProps.setRegionName(uniqueName);
    diskRegionProps.setOverflow(true);
    diskRegionProps.setRolling(true);
    diskRegionProps.setPersistBackup(true);

    DiskRegionHelperFactory.getSyncPersistOnlyRegion(cacheRule.getCache(), diskRegionProps,
        Scope.DISTRIBUTED_ACK);

    CacheServer cacheServer = cacheRule.getCache().addCacheServer();
    cacheServer.setPort(0);
    cacheServer.start();
    return cacheServer.getPort();
  }
If IOException occurs while updating an entry in an already initialized DiskRegion, then the
cache server should be stopped.

<p>
TRAC #39079: Regions with persistence remain in use after IOException have occurred
geode-core/src/distributedTest/java/org/apache/geode/internal/cache/InitializedDiskRegionWithIoExceptionRegressionTest.java