confl.txt

| Parameter                        | Description                                                                 | Default Value | Recommended Value |
|----------------------------------|-----------------------------------------------------------------------------|---------------|-------------------|
| `vm.swappiness`                  | Controls swap space usage.                                                  | 60            | 1                 |
| `vm.dirty_background_ratio`      | Percentage of system memory filled with dirty pages before flushing starts. | 10            | 5                 |
| `vm.dirty_ratio`                 | Maximum percentage of dirty pages before forced flushing.                   | 20            | 60                |
| `vm.dirty_expire_centisecs`      | Time after which dirty pages are eligible for write-out.                    | 3000          | 2000              |
| `vm.dirty_writeback_centisecs`   | Time between periodic write-out of dirty pages.                             | 500           | 100               |
| `net.core.somaxconn`             | Maximum number of connections that can be queued.                           | 128           | 4096              |
| `net.ipv4.tcp_max_syn_backlog`   | Maximum number of queued connection requests.                               | 1024          | 8096              |
| `net.core.netdev_max_backlog`    | Maximum number of packets in the network input queue.                       | 1000          | 5000              |
| `net.core.rmem_max`              | Maximum receive socket buffer size.                                         | 212992        | 16777216          |
| `net.core.wmem_max`              | Maximum send socket buffer size.                                            | 212992        | 16777216          |
| `net.ipv4.ttcp_rmem`              | Minimum, default, and maximum size for TCP receive buffers.                 | 4096 87380 6291456 | 4096 87380 16777216 |
| `net.ipv4.tcp_wmem`              | Minimum, default, and maximum size for TCP send buffers.                    | 4096 16384 4194304 | 4096 16384 16777216 |
| `fs.file-max`                    | Maximum number of file descriptors.                                         | 524288        | 1000000           |
| `fs.aio-max-nr`                  | Maximum number of allowed concurrent AIO requests.                          | 1048576       | 1048576           |
| `net.ipv4.tcp_fin_timeout`       | Time TCP should wait before closing a connection.                           | 60            | 30                |
| `net.ipv4.tcp_tw_reuse`          | Allows reuse of sockets in TIME_WAIT state.                                 | 0             | 1                 |
| `net.ipv4.ip_local_port_range`   | Defines the range of local ports available.                                 | 32768 60999   | 1024 65535        |
| `net.ipv4.tcp_syncookies`        | Enables SYN cookies to protect against SYN flood attacks.                   | 1             | 1                 |

conn.txt

| Parameter                      | Description                                                                                     | RHEL 7 Value        | RHEL 9 Default Value | New Value                  | Observations                       |
|--------------------------------|-------------------------------------------------------------------------------------------------|---------------------|----------------------|----------------------------|------------------------------------|
| `net.core.somaxconn`           | Maximum number of queued connections.                                                           | 128                 | 4096                 | 1024                       |                                    |
| `net.core.netdev_max_backlog`  | Maximum number of packets that can be queued on the input side.                                 | 1000                | 1000                 | 5000                       |                                    |
| `net.core.rmem_max`            | Maximum receive socket buffer size.                                                            | 212992              | 212992               | 16777216                   |                                    |
| `net.core.wmem_max`            | Maximum send socket buffer size.                                                               | 212992              | 212992               | 16777216                   |                                    |
| `net.ipv4.tcp_rmem`            | Minimum, default, and maximum size for TCP receive buffers.                                     | 4096 87380 6291456  | 4096 131072 6291456  | 4096 87380 16777216        |                                    |
| `net.ipv4.tcp_wmem`            | Minimum, default, and maximum size for TCP send buffers.                                       | 4096 16384 4194304  | 4096 16384 4194304   | 4096 65536 16777216        |                                    |
| `net.ipv4.tcp_max_syn_backlog` | Maximum number of remembered connection requests which have not received an acknowledgment.     | 128                 | 4096                 | 2048                       |                                    |
| `net.ipv4.tcp_fin_timeout`     | Time TCP should wait before closing a connection.                                              | 60                  | 60                   | 30                         |                                    |
| `net.ipv4.tcp_tw_reuse`        | Allows reuse of sockets in the TIME-WAIT state for new connections.                             | 0                   | 0                    | 1                          |                                    |
| `fs.file-max`                  | Maximum number of file handles that the kernel can allocate.                                   | 786432              | 9223372036854775807  | 2097152                    |                                    |
| `fs.nr_open`                   | Maximum number of file handles a process can allocate.                                         | 1048576             | 1048576              | 1048576                    |                                    |
| `net.ipv4.ip_local_port_range` | Defines the range of port numbers that are used for outgoing connections.                      | 32768 61000         | 32768 60999          | 1024 65535                 |                                    |
| NIC Offloading (TSO, GSO, GRO) | Ensures NIC offloading settings are optimized for high connection loads.                       | Not specified       | Not specified        | Enable as needed using ethtool |                                    |
| `isolcpus`                     | Isolates CPUs from the general scheduler, dedicating them to specific tasks.                    | Not set             | Not set              | `isolcpus=1-3`             |                                    |
| `irqbalance`                   | Ensures that interrupt handling is balanced across CPUs to prevent overload on a single CPU.    | Enabled             | Enabled              | Ensure running             |                                    |
| `vm.swappiness`                | Controls the tendency of the kernel to swap out inactive processes from RAM.                   | 30                  | 30                   | 10                         |                                    |
| `vm.dirty_ratio`               | Maximum percentage of system memory that can be filled with dirty pages before they are written to disk. | 20                  | 20                   | 20                         |                                    |
| `vm.dirty_background_ratio`    | Percentage of system memory that can be filled with dirty pages before background write-out starts. | 10                  | 10                   | 10                         |                                    |