NETWORK SETTINGS IN IBM I LPARs
Skytap has found that by optimizing network settings within IBM i for the conditions of a specific WAN, the throughput across the WAN can be greatly increased in some cases. Before changing a setting, the current setting should be recorded so it can be restored if a change has a negative effect.
|
SETTING |
GUIDE |
SUGGESTED |
DEFINITION |
|
Path MTU Discover (PMTUD) |
Configuring PMTUD | Enabled | Allows the protocol stack to determine the minimum MTU size on any network |
|
Maximum Transmission Unit (MTU) |
Configuring MTU | 1240 bytes | Restriction on largest possible packet allowed to leave the NIC |
|
rfc1323 |
Configuring rfc1323 | Enabled | Value of 1 indicates that tcp_sendspace and tcp_recvspace can exceed 64 KB |
|
TCP Send and Receive Buffers |
Configuring TCP Buffers | 4194304 | Specifies the maximum amount of TCP data can be buffered in the kernel before the application is blocked |
|
Large Send Offload (LSO) |
Configuring LSO | Enabled | Enable/Disable LARGESEND for virtual Ethernet AKA PLSO (true) |
|
IPv6 |
Configuring IPv6 | Disabled |
| OTHER | |
|
EC |
Sending data across a network requires some free CPU cycles, especially when thgat data is being encrypted/decrypted for transmission. Ensure the LPAR is not CPU starved. |
|
Multiple parallel stream transfers |
Sending multiple simultaneous streams of data is nearly always much more efficient than sending the data as a single TCP stream. Where ever possible, break the data sending into up to 6 simultaneous streams. |
You can learn more on this topic in the Skytap WAF
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