mfs.conf

The configuration file /opt/mapr/conf/mfs.conf specifies the following parameters about the MapR-FS server on each node.

WARNING: You must restart the FileServer after making changes to this file.

Parameters

Parameter	Default Value	Description
`mfs.server.ip`		IP address of the FileServer. For example, 192.168.10.10.
`mfs.server.port`	5660	Port used for communication with the server
`mfs.cache.lru.sizes`	Version 4.0.1:`inode:6:log:6:meta:10:dir:40:small:15` Version 4.0.2 and later versions: `inode:3:meta:6:small:27:dir:` `15:db:20:valc:3`	LRU cache configuration. The default value was changed in Version 4.0.2. See the notes on LRU Cache Configuration below this table.
`mfs.cache.memory`		Amount of system memory, in MB, reserved for use by the MFS cache. By default, this value is set to 20% of the system memory.
`mfs.on.virtual.machine`	0	Specifies whether MapR-FS is running on a virtual machine
`mfs.io.disk.timeout`	60	Timeout, in seconds, after which a disk is considered failed and taken offline. This parameter can be increased to tolerate slow disks.
`mfs.max.disks`	48	Maximum number of disks supported on a single node.
`mfs.max.logfile.size.in.mb`	1000MB	The maximum amount of disk space that the MFS logs can consume before the oldest log file is deleted; based on the following calculation: `maxSizePerLogFile = maxLogSize / MAX_NUM_OF_LOG_FILES` where `maxLogSize =` total amount of space that MFS log files can consume `MAX_NUM_OF_LOG_FILES =` total number of MFS log files
`mfs.subnets.whitelist`		A list of subnets (up to 256 characters) that are allowed to make requests to the FileServer service and access data on the cluster.
`mfs.disk.iothrottle.count`	100	The maximum number of outstanding requests on disk. NOTE: You can disable throttling by setting a high value.
`mfs.disk.resynciothrottle.factor`	20	The amount of time to wait before request is submitted to disk or sent over the network. Increasing the value will reduce the wait time and decreasing the value will increase the wait time. For example, setting the value to 40 will halve the wait time and setting the value to 10 will double the wait time.
`mfs.network.resynciothrottle.factor`	20	Controls the amount of time to wait before sending a resync operation over the network. Increasing the value will reduce the wait time and decreasing the value will increase the wait time. For example, setting the value to 40 will halve the wait time and setting the value to 10 will double the wait time.
`mfs.ssd.trim.enabled`	0	Set this parameter to 1 to enable TRIM operations for SSD devices. NOTE: Enable TRIM only if it is recommended by the SSD vendor.

Example

mfs.server.ip=192.168.10.10
mfs.server.port=5660
mfs.cache.lru.sizes=inode:3:meta:6:small:27:dir:15:db:20:val:3
mfs.on.virtual.machine=0
mfs.io.disk.timeout=60
mfs.max.disks=48

Notes on LRU Cache Configuration

The cache values are expressed as percentages, which vary based on the expected size of the data the node is required to cache. The goal is to achieve a state in which most of the required data comes directly from the cache. You may need to tune the cache percentages based on your cluster configuration and the workload on specific nodes. Non-default allocations tend to work better for nodes that run only CLDB and nodes that do not have CLDB but do have a heavy MapR-DB workload. Note the following recommendations.

For CLDB-only nodes, increase the size of the cache for Dir LRU to 40%: change dir:15 to dir:40A CLDB-only node is a fileserver node that hosts only the CLDB volume mapr.cldb.internal (no user volume data is hosted on the node). Dir LRU is used to host B-tree pages.

For non-CLDB nodes with no MapR-DB workload, optimize the cache to host as many file pages as possible. Change the value of the parameter to: inode:3:meta:6:small:27:dir:6

The remainder of the cache will be used to cache file data pages.

Note: You need to restart MFS in order for the change in mfs.conf to take effect.