address matei's comments

core/src/main/scala/org/apache/spark/executor/ExecutorExitCode.scala

@@ -41,7 +41,7 @@ object ExecutorExitCode {
   /** DiskStore failed to create a local temporary directory after many attempts. */
   val DISK_STORE_FAILED_TO_CREATE_DIR = 53
 
-  /** TachyonStore failed to create a local temporary directory after many attempts. */
+  /** TachyonStore failed to initialize after many attempts. */
   val TACHYON_STORE_FAILED_TO_INITIALIZE = 54
 
   /** TachyonStore failed to create a local temporary directory after many attempts. */
@@ -54,6 +54,9 @@ object ExecutorExitCode {
       case OOM => "OutOfMemoryError"
       case DISK_STORE_FAILED_TO_CREATE_DIR =>
         "Failed to create local directory (bad spark.local.dir?)"
+      case TACHYON_STORE_FAILED_TO_INITIALIZE => "TachyonStore failed to initialize."
+      case TACHYON_STORE_FAILED_TO_CREATE_DIR =>
+        "TachyonStore failed to create a local temporary directory."
       case _ => 
         "Unknown executor exit code (" + exitCode + ")" + (
           if (exitCode > 128) {

core/src/main/scala/org/apache/spark/storage/BlockManager.scala

@@ -62,7 +62,7 @@ private[spark] class BlockManager(
     val storeDir = conf.get("spark.tachyonStore.baseDir", System.getProperty("java.io.tmpdir"))
     val appFolderName = conf.get("spark.tachyonStore.folderName")
     val tachyonStorePath = s"${storeDir}/${appFolderName}/${this.executorId}"
-    val tachyonMaster = conf.get("spark.tachyonStore.URL",  "tachyon://localhost:19998")
+    val tachyonMaster = conf.get("spark.tachyonStore.url",  "tachyon://localhost:19998")
     val tachyonBlockManager = new TachyonBlockManager(
       shuffleBlockManager, tachyonStorePath, tachyonMaster)
     tachyonInitialized = true
@@ -276,7 +276,7 @@ private[spark] class BlockManager(
           (StorageLevel.NONE, 0L, 0L, 0L)
         case level =>
           val inMem = level.useMemory && memoryStore.contains(blockId)
-          val inTachyon = level.useTachyon && tachyonStore.contains(blockId)
+          val inTachyon = level.useOffHeap && tachyonStore.contains(blockId)
           val onDisk = level.useDisk && diskStore.contains(blockId)
           val deserialized = if (inMem) level.deserialized else false
           val replication = if (inMem || inTachyon || onDisk) level.replication else 1
@@ -369,7 +369,7 @@ private[spark] class BlockManager(
         }
 
         // Look for the block in Tachyon
-        if (level.useTachyon) {
+        if (level.useOffHeap) {
           logDebug("Getting block " + blockId + " from tachyon")
           if (tachyonStore.contains(blockId)) {
             tachyonStore.getBytes(blockId) match {
@@ -651,7 +651,7 @@ private[spark] class BlockManager(
           }
           // Keep track of which blocks are dropped from memory
           res.droppedBlocks.foreach { block => updatedBlocks += block }
-        } else if (level.useTachyon) {
+        } else if (level.useOffHeap) {
           // Save to Tachyon.
           val askForBytes = level.replication > 1
           val res = data match {
@@ -757,7 +757,7 @@ private[spark] class BlockManager(
   var cachedPeers: Seq[BlockManagerId] = null
   private def replicate(blockId: BlockId, data: ByteBuffer, level: StorageLevel) {
     val tLevel = StorageLevel(
-      level.useDisk, level.useMemory, level.useTachyon, level.deserialized, 1)
+      level.useDisk, level.useMemory, level.useOffHeap, level.deserialized, 1)
     if (cachedPeers == null) {
       cachedPeers = master.getPeers(blockManagerId, level.replication - 1)
     }
@@ -922,7 +922,7 @@ private[spark] class BlockManager(
           if (level.useDisk) {
             diskStore.remove(id)
           }
-          if (level.useTachyon) {
+          if (level.useOffHeap) {
             tachyonStore.remove(id)
           }
           iterator.remove()

core/src/main/scala/org/apache/spark/storage/BlockManagerMasterActor.scala

@@ -375,7 +375,7 @@ private[spark] class BlockManagerInfo(
         logInfo("Added %s on disk on %s (size: %s)".format(
           blockId, blockManagerId.hostPort, Utils.bytesToString(diskSize)))
       }
-      if (storageLevel.useTachyon) {
+      if (storageLevel.useOffHeap) {
         _blocks.put(blockId, BlockStatus(storageLevel, 0, 0, tachyonSize))
         logInfo("Added %s on tachyon on %s (size: %s)".format(
           blockId, blockManagerId.hostPort, Utils.bytesToString(tachyonSize)))
@@ -394,7 +394,7 @@ private[spark] class BlockManagerInfo(
         logInfo("Removed %s on %s on disk (size: %s)".format(
           blockId, blockManagerId.hostPort, Utils.bytesToString(blockStatus.diskSize)))
       }
-      if (blockStatus.storageLevel.useTachyon) {
+      if (blockStatus.storageLevel.useOffHeap) {
         logInfo("Removed %s on %s on tachyon (size: %s)".format(
           blockId, blockManagerId.hostPort, Utils.bytesToString(blockStatus.tachyonSize)))
       }

core/src/main/scala/org/apache/spark/storage/StorageLevel.scala

@@ -31,7 +31,7 @@ import java.io.{Externalizable, IOException, ObjectInput, ObjectOutput}
 class StorageLevel private(
     private var useDisk_ : Boolean,
     private var useMemory_ : Boolean,
-    private var useTachyon_ : Boolean,
+    private var useOffHeap_ : Boolean,
     private var deserialized_ : Boolean,
     private var replication_ : Int = 1)
   extends Externalizable {
@@ -45,27 +45,27 @@ class StorageLevel private(
 
   def useDisk = useDisk_
   def useMemory = useMemory_
-  def useTachyon = useTachyon_
+  def useOffHeap = useOffHeap_
   def deserialized = deserialized_
   def replication = replication_
 
   assert(replication < 40, "Replication restricted to be less than 40 for calculating hashcodes")
 
   override def clone(): StorageLevel = new StorageLevel(
-    this.useDisk, this.useMemory, this.useTachyon, this.deserialized, this.replication)
+    this.useDisk, this.useMemory, this.useOffHeap, this.deserialized, this.replication)
 
   override def equals(other: Any): Boolean = other match {
     case s: StorageLevel =>
       s.useDisk == useDisk &&
       s.useMemory == useMemory &&
-      s.useTachyon == useTachyon &&
+      s.useOffHeap == useOffHeap &&
       s.deserialized == deserialized &&
       s.replication == replication
     case _ =>
       false
   }
 
-  def isValid = ((useMemory || useDisk || useTachyon) && (replication > 0))
+  def isValid = ((useMemory || useDisk || useOffHeap) && (replication > 0))
 
   def toInt: Int = {
     var ret = 0
@@ -75,7 +75,7 @@ class StorageLevel private(
     if (useMemory_) {
       ret |= 4
     }
-    if (useTachyon_) {
+    if (useOffHeap_) {
       ret |= 2
     }
     if (deserialized_) {
@@ -93,7 +93,7 @@ class StorageLevel private(
     val flags = in.readByte()
     useDisk_ = (flags & 8) != 0
     useMemory_ = (flags & 4) != 0
-    useTachyon_ = (flags & 2) != 0
+    useOffHeap_ = (flags & 2) != 0
     deserialized_ = (flags & 1) != 0
     replication_ = in.readByte()
   }
@@ -102,14 +102,14 @@ class StorageLevel private(
   private def readResolve(): Object = StorageLevel.getCachedStorageLevel(this)
 
   override def toString: String = "StorageLevel(%b, %b, %b, %b, %d)".format(
-    useDisk, useMemory, useTachyon, deserialized, replication)
+    useDisk, useMemory, useOffHeap, deserialized, replication)
 
   override def hashCode(): Int = toInt * 41 + replication
   def description : String = {
     var result = ""
     result += (if (useDisk) "Disk " else "")
     result += (if (useMemory) "Memory " else "")
-    result += (if (useTachyon) "Tachyon " else "")
+    result += (if (useOffHeap) "Tachyon " else "")
     result += (if (deserialized) "Deserialized " else "Serialized ")
     result += "%sx Replicated".format(replication)
     result
@@ -135,10 +135,10 @@ object StorageLevel {
   val MEMORY_AND_DISK_SER_2 = new StorageLevel(true, true, false, false, 2)
   val OFF_HEAP = new StorageLevel(false, false, true, false)
 
-  /** Create a new StorageLevel object without setting useTachyon*/
-  def apply(useDisk: Boolean, useMemory: Boolean, useTachyon: Boolean, 
+  /** Create a new StorageLevel object without setting useOffHeap*/
+  def apply(useDisk: Boolean, useMemory: Boolean, useOffHeap: Boolean,
     deserialized: Boolean, replication: Int) = getCachedStorageLevel(
-      new StorageLevel(useDisk, useMemory, useTachyon, deserialized, replication))
+      new StorageLevel(useDisk, useMemory, useOffHeap, deserialized, replication))
 
   /** Create a new StorageLevel object */
   def apply(useDisk: Boolean, useMemory: Boolean,

core/src/main/scala/org/apache/spark/util/JsonProtocol.scala

@@ -281,7 +281,7 @@ private[spark] object JsonProtocol {
   def storageLevelToJson(storageLevel: StorageLevel): JValue = {
     ("Use Disk" -> storageLevel.useDisk) ~
     ("Use Memory" -> storageLevel.useMemory) ~
-    ("Use Tachyon" -> storageLevel.useTachyon) ~
+    ("Use Tachyon" -> storageLevel.useOffHeap) ~
     ("Deserialized" -> storageLevel.deserialized) ~
     ("Replication" -> storageLevel.replication)
   }

docs/configuration.md

@@ -126,12 +126,12 @@ Apart from these, the following properties are also available, and may be useful
   <td>spark.tachyonStore.baseDir</td>
   <td>System.getProperty("java.io.tmpdir")</td>
   <td>
-    Directories of the Tachyon File System that store RDDs. The Tachyon file system's URL is set by <code>spark.tachyonStore.URL</code>.
+    Directories of the Tachyon File System that store RDDs. The Tachyon file system's URL is set by <code>spark.tachyonStore.url</code>.
     It can also be a comma-separated list of multiple directories on Tachyon file system.
   </td>
 </tr>
 <tr>
-  <td>spark.tachyonStore.URL</td>
+  <td>spark.tachyonStore.url</td>
   <td>tachyon://localhost:19998</td>
   <td>
     The URL of the underlying Tachyon file system in the TachyonStore.

examples/src/main/scala/org/apache/spark/examples/SparkTachyonPi.scala

@@ -22,7 +22,8 @@ import scala.math.random
 import org.apache.spark._
 import org.apache.spark.storage.StorageLevel
 
-/** Computes an approximation to pi 
+/**
+ *  Computes an approximation to pi
  *  This example uses Tachyon to persist rdds during computation.
  */
 object SparkTachyonPi {
@@ -44,16 +45,7 @@ object SparkTachyonPi {
       val y = random * 2 - 1
       if (x * x + y * y < 1) 1 else 0
     }.reduce(_ + _)
-    println("1- Pi is roughly " + 4.0 * count / n)
-
-    val rdd2 = spark.parallelize(1 to n, slices)
-    rdd2.persist(StorageLevel.OFF_HEAP)
-    val count2 = rdd2.map { i =>
-      val x = random * 2 - 1
-      val y = random * 2 - 1
-      if (x * x + y * y < 1) 1 else 0
-    }.reduce(_ + _)
-    println("2- Pi is roughly " + 4.0 * count2 / n)
+    println("Pi is roughly " + 4.0 * count / n)
 
     spark.stop()
   }

python/pyspark/storagelevel.py

@@ -34,7 +34,7 @@ def __init__(self, useDisk, useMemory, useTachyon, deserialized, replication = 1
 
     def __repr__(self):
         return "StorageLevel(%s, %s, %s, %s, %s)" % (
-            self.useDisk, self.useMemory, self.useTachyon, self.deserialized, self.replication)
+            self.useDisk, self.useMemory, self.useOffHeap, self.deserialized, self.replication)
 
 StorageLevel.DISK_ONLY = StorageLevel(True, False, False, False)
 StorageLevel.DISK_ONLY_2 = StorageLevel(True, False, False, False, 2)
@@ -46,4 +46,4 @@ def __repr__(self):
 StorageLevel.MEMORY_AND_DISK_2 = StorageLevel(True, True, False, True, 2)
 StorageLevel.MEMORY_AND_DISK_SER = StorageLevel(True, True, False, False)
 StorageLevel.MEMORY_AND_DISK_SER_2 = StorageLevel(True, True, False, False, 2)
-StorageLevel.TACHYON = StorageLevel(False, False, True, False, 1)
+StorageLevel.OFF_HEAP = StorageLevel(False, False, True, False, 1)