MongoDB Documentation, Release 3.0.4 • Disable NUMA or set vm.zone_reclaim_mode to 0 and run mongod instances with node interleaving. See: MongoDB and NUMA Hardware (page 200) for more information. • Adjust the ulimit values on your hardware to suit your use case. If multiple mongod or mongos instances are running under the same user, scale the ulimit values accordingly. See: UNIX ulimit Settings (page 287) for more information. • Use noatime for the dbPath mount point. • Configure sufficient file handles ( fs.file-max ), kernel pid limit ( kernel.pid_max ), and maximum threads per process ( kernel.threads-max ) for your deployment. For large systems, values of 98000, 32768, and 64000 are a good starting point. • Ensure that your system has swap space configured. Refer to your operating system’s documentation for details on appropriate sizing. • Ensure that the system default TCP keepalive is set correctly. A value of 300 often provides better performance for replica sets and sharded clusters. See: Does TCP keepalive time affect MongoDB Deployments? (page 779) in the Frequently Asked Questions for more information. • Consider disabling NTFS “last access time” updates. This is analogous to disabling atime on Unix-like sys- tems. • Schedule periodic tests of your back up and restore process to have time estimates on hand, and to verify its functionality. • Use MongoDB Cloud Manager 119 or Ops Manager, an on-premise solution available in MongoDB Enterprise Advanced 120 or another monitoring system to monitor key database metrics and set up alerts for them. Include alerts for the following metrics: – lock percent (for the MMAPv1 storage engine (page 91)) – replication lag – replication oplog window – assertions – queues – page faults • Monitor hardware statistics for your servers. In particular, pay attention to the disk use, CPU, and available disk space. – Create a dummy 4GB file on the storage.dbPath drive to ensure available space if the disk becomes full. In the absence of disk space monitoring, or as a precaution: Windows Backups Monitoring $^{119}$https://cloud.mongodb.com/?jmp=docs $^{120}$https://www.mongodb.com/products/mongodb-enterprise-advanced?jmp=docs 313 5.4. Production Checklist