title: PHP: Unknown: Failed to write session data (memcache)
body: <p>I'm stored session in memcached with php and seeing the following logged a lot in the php error log:</p>
  
  <pre><code>[31-Oct-2014 03:33:11 UTC] PHP Warning:  Unknown: Failed to write session data (memcache). Please verify that the current setting of session.save_path is correct (tcp://localhost:11211?persistent=1&amp;amp;weight=1&amp;amp;timeout=1&amp;amp;retry_interval=3) in Unknown on line 0
  </code></pre>
  
  <p>Here is the memcached.conf:</p>
  
  <pre><code>  # Memcached Configuration Settings
  
  # IP address to listen on
  # The default is INARR_ANY, any network interface
  HOST="127.0.0.1"
  
  # TCP port to listen on
  # The default is 11211
  TCP_PORT="11211"
  
  # UDP port to listen on
  # Can be disabled by setting it to 0.
  # The default is 11211
  UDP_PORT="11211"
  
  # Unix socket path to listen on
  # Using a socket will automatically disable networking support.
  # The default is /var/run/memcached/memcached.sock
  SOCKET=""
  
  # Client binding protocol
  # Available options: auto, ascii, binary
  # The default is auto
  PROTOCOL="auto"
  
  # Number of threads used to process incoming requests
  # Not useful to set higher than the number of server CPU cores.
  # The default is 4
  THREADS="4"
  
  # Maximum memory to use for object storage
  # The default is 64 megabytes
  MAX_BYTES="128"
  
  # Maximum simultaneous connections
  # The default is 1024
  MAX_CONNECTIONS="2048"
  
  # Maximum sequential requests
  # Prevents client starvation by setting a limit to the number
  # of requests the server will process from a client connection.
  # The default is 20
  MAX_REQUESTS="50"
  
  # Multiplier factor for computing the size of item memory chunks
  # The default is 1.25
  CHUNK_FACTOR="1.25"
  
  # Minimum number of bytes for an item memory chunk
  # The default is 48 bytes
  CHUNK_SIZE="48"
  
  # Default size of each slab page
  # Adjusting this value changes the item size limit, increases
  # the number of slabs and overal memory usage.
  # Choose a value between is 1 kilobyte and 128 megabytes.
  # The default is 1 megabyte
  SLAB_SIZE="1m"
  
  # Additional server options
  OPTIONS=""
  </code></pre>
  
  <p>Any idea what I can do to fix this?</p>