General Configuration¶

The LSMCD configuration file is located at /usr/local/lsmcd/conf/node.conf. This guide will explain the list of the available configuration options within the file.

A sample node.conf is included with LSMCD. It might be easier initially to copy the file from the distribution to the destination and make changes to it from there. Notes are discussed which mention the changes you will need to make and some recommended changes.

A comment is started with a pound sign # in the first column. A blank line is ignored. The configuration titles are case insensitive (can be any mix of upper and lower case), but the values are case sensitive (for strings) but true/false values can be mixed case.

CacheD Configurations¶

These options configure the CacheD portion of LSMCD.

Cached.Addr is the LSMCD public listening address and port. This is the address used when connecting and interacting with LSMCD. If replacing Memcached, this should match the current Memcached listening address. You must stop memcached before starting LSMCD. Cached.Addr=127.0.0.1:11211

If you will be using LSMCD entirely within a single machine and do not need it to listen on a IP port, you can specify a UNIX Domain Socket file name for extra security. For example, using the socket name /tmp/lsmcd.sock specify: Cached.Addr=UDS:///tmp/lsmcd.sock If you are using UNIX domain sockets, see your memcached language guide for connecting to it. For example, for PHP, you specify the domain socket file name as the first parameter (hostName) to addServer and a 0 as the second parameter (port).

Cached.Slices¶

Cached.Slices is the number of slices that the data will be stored in. This should be equal to or higher than CachedProcCnt to minimize lock contention. Cached.Slices=2

Cached.Slice.Priority¶

Cached.Slice.Priority is the priority of the slice in the replication group. This is explained in detail here.

Cached.Slice.Priority.0=100
Cached.Slice.Priority.1=200
#Cached.Slice.Priority.2=300
#Cached.Slice.Priority.3=400


Cached.ShmDir¶

Cached.ShmDir defines the location of LSMCD data files, such as cache data. If /dev/shm is used, the data will be stored in memory, but will be lost after a server reboot. If using the regular disk, data will be persistent, but it will be slower due to disk I/O. It is recommended to use an SSD for data storage, as SSDs will provide faster performance while keeping data persistent.

Cached.ShmDir=/dev/shm/lsmcd


Cached.HashTableName¶

Cached.HashTableName is the global hash table name. There is no need to have a different setting per slice. #Cached.HashTableName=memcache

User and Group¶

The User and Group options define the user and group that LSCMD will run as.

User=nobody
Group=nobody


CachedProcCnt¶

The CachedProcCnt setting determines how many LSMCD processes will run. LSMCD uses multiprocessing unlike MemcacheD, which uses multithreading. The recommended value is no more than the number of CPUs in your system.

CachedProcCnt=4


TmpDir¶

TmpDir specifies the location of the LSMCD pid file and is generally unchanged by most users. TmpDir=/tmp/lsmcd

LogLevel¶

LogLevel determines the level of the log messages output in LSMCD. Example levels include Info, Error, Warn, Notice, Info, Debug (as well as dbg_high, dbg_medium, dbg_low) and Trace.

You may be asked to set the LogLevel to dbg_medium at the request of technical support if you have a problem, but it should not be left any higher than Notice or else you risk filling your disk unnecessarily.

LogLevel=notice
#LogLevel=dbg_medium


LogFile¶

LogFile specifies the location of the LSMCD log file. It should be checked for any problems or issues. Most users will leave it at the default location so it can be found in the event of a technical support issue. LogFile=/tmp/lsmcd.log

Cached.UseSasl¶

Cached.UseSasl should be set to TRUE if you wish to enable SASL in your memcached installation. This requires that your application provide a user and password with every transaction and you can not use telnet. SASL is described here CACHED.USESASL=TRUE

Once you have changed this value, you must delete your existing LSMCD files: rm -rf /dev/shm/lsmcd

Cached.DataByUser¶

Can only be used if Cached.UseSasl=TRUE and if no replication is used. If set to true, each SASL user will be allocated an individual set of data within the data pool. When memcached requests are preceded by a user authorization (which is always the case unless you are using legacy code and enable the Cached.Anonymous option) the request is always for the user specified in the request whether it's a get, put, or stats. See the SASL documentation for details on use.

Cached.Anonymous¶

Can only be used if Cached.UseSasl=TRUE and if no replication is used. While legacy apps (those without user/password validation) can be made to work with this option until they've all been updated, it makes the most sense if you've specified Cached.DataByUser=true. If set to true, users without validation code can access the system, but operate within the common area and do not affect the user specified data areas. See the SASL documentation for details on use.

Cached.SaslDB¶

Can only be used if Cached.UseSasl=TRUE and if no replication is used. Allows you to specify a database name other than the default sasl database of /etc/sasldb2. Recommended in very secure sensitive environments. See the SASL section for use of this option particularly with saslpasswd2 and sasldblistusers2.

Cached.MemMaxSz¶

If set to a non-zero value, it is the number of bytes that will be stored in the hash before least recently used items begin to be purged. The default is 64000000.

Cached.UserSize¶

If user level databases are turned on, the initial size of each user's database. The default is 1000.

Cached.HashSize¶

The default initial cache entry size in bytes. Defaults to 500000. The maximum size is controlled with Cached.MemMaxSz.

Cached.ValMaxSz¶

The maximum size of any individual entry in the cache. 0 disables the limit, the default is 1000000.

Replicator Configurations¶

These options configure the replication portion of LSMCD. If there is no replication group, none of these parameters are required. Replication can't be used with SASL.

Repl.LbAddrs is a comma separated list of IP addresses (with port number) that form the replication group. This is always required for replication and should be two or more address/port number entries, comma separated. Repl.LbAddrs=127.0.0.1:12340,192.168.0.122:12340

Cached.PriAddr is the LSMCD private listening address and port used for interactions between LSMCD instances. Required for replication. Cached.PriAddr=127.0.0.1:11000

Repl.ListenSvrAddr is a required parameter which is the IP address and port that lsmcd will be listening on. Required for replication. Most users will use: Repl.ListenSvrAddr=127.0.0.1:12340

Repl.DispatchAddr is a replication required parameter. It is recommended that it be specified as: Repl.DispatchAddr=127.0.0.1:5501

RepldSockPath¶

RepldSockPath specifies the location of the Repld sock file. RepldSockPath=/tmp/repld.usock

CachedSockPath¶

CachedSockPath specifies the location of the Cached sock file and is required. The extra dot at the end is important as this is used as a prefix for a number of separate files. CachedSockPath=/tmp/cached.usock.

Repl.HeartBeatReq¶

Repl.HeartBeatReq is the frequency of the replication heartbeat. Repl.HeartBeatReq=5

Repl.HeartBeatRetry¶

Repl.HeartBeatRetry is the maximum timeout for replication heartbeat. Repl.HeartBeatRetry=30

Repl.MaxTidPacket¶

Repl.MaxTidPacket is the maximum replication packet size. Repl.MaxTidPacket=2048000

Repl.GzipStream¶

Repl.GzipStream indicates whether or not LSMCD should use gzip stream for replication traffic. Repl.GzipStream=YES

Last update: July 12, 2021