rbd: Fix to cleanly reject -drive without pool or image

[mirror_qemu.git] / docs / replay.txt

diff --git a/docs/replay.txt b/docs/replay.txt
index 347b2ff0556284723b683cc027fb1bb4ef3f1f28..486c1e0e9d5a433905475e87506b679e33dc0776 100644 (file)
--- a/docs/replay.txt
+++ b/docs/replay.txt
@@ -196,6 +196,22 @@ is recorded to the log. In replay phase the queue is matched with
 events read from the log. Therefore block devices requests are processed
 deterministically.
 
+Snapshotting
+------------
+
+New VM snapshots may be created in replay mode. They can be used later
+to recover the desired VM state. All VM states created in replay mode
+are associated with the moment of time in the replay scenario.
+After recovering the VM state replay will start from that position.
+
+Default starting snapshot name may be specified with icount field
+rrsnapshot as follows:
+ -icount shift=7,rr=record,rrfile=replay.bin,rrsnapshot=snapshot_name
+
+This snapshot is created at start of recording and restored at start
+of replaying. It also can be loaded while replaying to roll back
+the execution.
+
 Network devices
 ---------------
 
@@ -209,3 +225,10 @@ recording the virtual machine this filter puts all packets coming from
 the outer world into the log. In replay mode packets from the log are
 injected into the network device. All interactions with network backend
 in replay mode are disabled.
+
+Audio devices
+-------------
+
+Audio data is recorded and replay automatically. The command line for recording
+and replaying must contain identical specifications of audio hardware, e.g.:
+ -soundhw ac97