Colleagues!
I'm running php 5.3 (5.3.8) with memcache (2.2.6) client library (http://pecl.php.net/package/memcache) to deal with memcached server. My goal is to have failover solution for sessions engine, namely:
What I expect is that in case if one of memcached servers is down, php will attempt to utilize the second server in the pool [will successfully connect it and become happy], however when first memcached server in the pool is down I'm receiving the following error:
Session start failed. Original message: session_start(): Server 10.0.10.111 (tcp 11211) failed with: Connection refused (111)
while relevant php settings are:
session.save_handler memcache
session.save_path tcp://10.0.10.111:11211?persistent=1&weight=1&timeout=1&retry_interval=10, tcp://10.0.10.110:11211?persistent=1&weight=1&timeout=1&retry_interval=10
and memcache settings (while I think that it's near to standard) are:
Directive Local Value
memcache.allow_failover 1
memcache.chunk_size 8192
memcache.default_port 11211
memcache.default_timeout_ms 1000
memcache.hash_function crc32
memcache.hash_strategy standard
memcache.max_failover_attempts 20
Memcached still running on the second server and perfectly accessible from the WEB server:
telnet 10.0.10.110 11211
Trying 10.0.10.110...
Connected to 10.0.10.110 (10.0.10.110).
Escape character is '^]'.
get aaa
END
quit
Connection closed by foreign host.
So in other words, instead of querying all of the listed servers sequentially it crashes after unsuccessful attempt to connect the first server in the queue. Finally I do realize that there are releases of 3.0.x client library available, however it does not look too reliable for me as it still in beta version.
Please advice how can I get desired behavior with standard PHP, client lib and server.
Thanks a lot!
Best, Eugene
I would like to thank everybody who participated this question, the answer is the following: in reality memcache (not memcached) as session handler supports comma separated servers as the session.save_path, moreover it supports failover. The error mentioned above Session start failed. Original message: session_start(): Server 10.0.10.111 (tcp 11211) failed with: Connection refused (111) had only 8th (Notice) level. In fact engine just informs you about the fact that one of the servers is unavailable (which is logical, as otherwise how will you know?) and then successfully connects to the second server and using it.
So all of the misunderstanding has been caused by weak documentation, memcache/memcached confusions and paranoid (E_ALL) settings of my custom error handler. In the meantime the issue has been resolved by ignoring notices referring to error Connection refused (111) in the session establishing context