/// <summary>
/// Confirm that FSImage files in all StorageDirectory are the same,
/// and non-empty, and there are the expected number of them.
/// </summary>
/// <param name="fsn">- the FSNamesystem being checked.</param>
/// <param name="numImageDirs">- the configured number of StorageDirectory of type IMAGE.
/// </param>
/// <returns>- the md5 hash of the most recent FSImage files, which must all be the same.
/// </returns>
/// <exception cref="System.Exception">
/// if image files are empty or different,
/// if less than two StorageDirectory are provided, or if the
/// actual number of StorageDirectory is less than configured.
/// </exception>
public static string CheckImages(FSNamesystem fsn, int numImageDirs)
{
NNStorage stg = fsn.GetFSImage().GetStorage();
//any failed StorageDirectory is removed from the storageDirs list
NUnit.Framework.Assert.AreEqual("Some StorageDirectories failed Upgrade", numImageDirs
, stg.GetNumStorageDirs(NNStorage.NameNodeDirType.Image));
NUnit.Framework.Assert.IsTrue("Not enough fsimage copies in MiniDFSCluster " + "to test parallel write"
, numImageDirs > 1);
// List of "current/" directory from each SD
IList <FilePath> dirs = FSImageTestUtil.GetCurrentDirs(stg, NNStorage.NameNodeDirType
.Image);
// across directories, all files with same names should be identical hashes
FSImageTestUtil.AssertParallelFilesAreIdentical(dirs, Sharpen.Collections.EmptySet
<string>());
FSImageTestUtil.AssertSameNewestImage(dirs);
// Return the hash of the newest image file
Storage.StorageDirectory firstSd = stg.DirIterator(NNStorage.NameNodeDirType.Image
).Next();
FilePath latestImage = FSImageTestUtil.FindLatestImageFile(firstSd);
string md5 = FSImageTestUtil.GetImageFileMD5IgnoringTxId(latestImage);
System.Console.Error.WriteLine("md5 of " + latestImage + ": " + md5);
return(md5);
}
