Each machine that will run VMware GemFire must meet the following requirements:
- Java SE Development Kit 8 with update 272 or a more recent version 8 update. The same versions are supported with OpenJDK. GemFire is compatible with Open JDK 11 (HotSpot). See Java Support for details.
- An adequate per-user limit on the number of file descriptors; for Unix/Linux, the recommended soft limit is 8192, and the hard limit is 81920.
- An adequate per-user limit on the number of processes (nproc); for Unix/Linux, the recommended soft limit is 501408, with an unlimited hard limit.
- A system clock set to the correct time and a time synchronization service such as Network Time Protocol (NTP). Correct time stamps permit the following activities:
- Logs that are useful for troubleshooting. Synchronized time stamps ensure that log messages from different hosts can be merged to reproduce an accurate chronological history of a distributed run.
- Aggregate product-level and application-level time statistics.
- Accurate monitoring of the GemFire system with scripts and other tools that read the system statistics and log files.
- The host name and host files are properly configured for the machine. The host name and host file configuration can affect
gfsh and Pulse functionality.
Deactivate TCP SYN cookies. Most default Linux installations use SYN cookies to protect the system against malicious attacks that flood TCP SYN packets, but this feature is not compatible with stable and busy GemFire clusters. Security implementations should instead seek to prevent attacks by placing GemFire server clusters behind advanced firewall protection.
To deactivate SYN cookies permanently:
/etc/sysctl.conf file to include the following line:
net.ipv4.tcp_syncookies = 0
Setting this value to zero deactivates SYN cookies.