Xen devel - Apr 2011 - [SPAM] [PATCH] remus: blackhole replication target

# HG changeset patch
# User Shriram Rajagopalan <rshriram@cs.ubc.ca>
# Date 1302206497 25200
# Node ID d7b7aef658dd962e13d29c851a28fde89b690e2e
# Parent  a73514445065390ae70c44e1708971dd6fa2a6f0
remus: blackhole replication target

The new --null option allows one to test and play with just the
memory checkpointing and network buffering aspect of remus, without
the need for a second host. The disk is not replicated. All replication
data is sent to /dev/null. This option is pretty handy when a user
wants to see the page churn for his workload or observe the latency hit
though the latter will not be accurate.

Signed-off-by: Shriram Rajagopalan <rshriram@cs.ubc.ca>

diff -r a73514445065 -r d7b7aef658dd tools/python/xen/remus/save.py
--- a/tools/python/xen/remus/save.py	Thu Apr 07 12:36:39 2011 -0700
+++ b/tools/python/xen/remus/save.py	Thu Apr 07 13:01:37 2011 -0700
@@ -95,6 +95,12 @@
         self.sock = sock
         super(MigrationSocket, self).__init__(fd)
 
+class NullSocket(_proxy):
+    def __init__(self, address):
+        filedesc = os.open(''/dev/null'', 0666)
+        fd = os.fdopen(filedesc, ''w+'')
+        super(NullSocket, self).__init__(fd)
+
 class Keepalive(object):
     "Call a keepalive method at intervals"
     def __init__(self, method, interval=0.1):
diff -r a73514445065 -r d7b7aef658dd tools/remus/remus
--- a/tools/remus/remus	Thu Apr 07 12:36:39 2011 -0700
+++ b/tools/remus/remus	Thu Apr 07 13:01:37 2011 -0700
@@ -21,6 +21,7 @@
         self.domid = 0
 
         self.host = ''localhost''
+        self.nullremus = False
         self.port = XendOptions.instance().get_xend_relocation_port()
         self.interval = 200
         self.netbuffer = True
@@ -33,6 +34,8 @@
                           help=''checkpoint every MS
milliseconds'')
         parser.add_option(''-p'', ''--port'',
dest=''port'', type=''int'',
                           help=''send stream to port PORT'',
metavar=''PORT'')
+        parser.add_option('''',
''--blackhole'', dest=''nullremus'',
action=''store_true'',
+                          help=''replicate to /dev/null (no disk
checkpoints, only memory & net buffering)'')
         parser.add_option('''', ''--no-net'',
dest=''nonet'', action=''store_true'',
                           help=''run without net buffering (benchmark
option)'')
         parser.add_option('''', ''--timer'',
dest=''timer'', action=''store_true'',
@@ -49,6 +52,8 @@
             self.interval = opts.interval
         if opts.port:
             self.port = opts.port
+        if opts.nullremus:
+            self.nullremus = True
         if opts.nonet:
             self.netbuffer = False
         if opts.timer:
@@ -107,18 +112,22 @@
     bufs = []
 
     # disks must commit before network can be released
-    for disk in dom.disks:
-        try:
-            bufs.append(ReplicatedDisk(disk))
-        except ReplicatedDiskException, e:
-            print e
-            continue
+    if not cfg.nullremus:
+        for disk in dom.disks:
+            try:
+                bufs.append(ReplicatedDisk(disk))
+            except ReplicatedDiskException, e:
+                print e
+                continue
 
     if cfg.netbuffer:
         for vif in dom.vifs:
             bufs.append(BufferedNIC(vif))
 
-    fd = save.MigrationSocket((cfg.host, cfg.port))
+    if cfg.nullremus:
+        fd = save.NullSocket((cfg.host, cfg.port))
+    else:
+        fd = save.MigrationSocket((cfg.host, cfg.port))
 
     def postsuspend():
         ''Begin external checkpointing after domain has
paused''

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