|
Parameter group |
Parameter |
AIX 5.3 default setting |
AIX 6.1 default setting |
DB2 best practice |
Comments |
|
ioo |
j2_maxPageReadAhead |
128 |
128 |
128 |
The vmo tunable minfree is at least set to this value. |
|
ioo |
j2_maxRandomWrite |
128 |
0 |
0 |
Random write behind is disabled hence the file pages flushed to disk only during sync. |
|
ioo |
j2_minPageReadAhead |
2 |
2 |
2 |
No change in value from AIX 5.3. |
|
ioo |
j2_nBufferPerPagerDevice |
512 |
512 |
512 |
Restricted tunable in AIX 6.1. |
|
ioo |
maxpgahead |
128 |
8 |
8 |
Restricted tunable in AIX 6.1 |
|
ioo |
maxrandwrt |
128 |
0 |
0 |
Restricted tunable in AIX 6.1.Similar to JFS Random write. |
|
ioo |
minpgahead |
2 |
2 |
2 |
No change in value from AIX 5.3. |
|
ioo |
numfsbufs |
4096 |
196 |
196 |
Restricted tunable in AIX 6.1 |
|
ioo |
sync_release_ilock |
1 |
0 |
0 |
Restricted tunable in AIX 6.1. |
|
no |
bcastping |
0 |
0 |
0 |
No change in value from AIX 5.3. |
|
no |
clean_partial_conns |
1 |
0 |
1 |
Enabled to overcome SYNC attack. |
|
no |
directed_broadcast |
0 |
0 |
0 |
Enabled to overcome SYNC attack. |
|
no |
extendednetstats |
|
0 |
0 |
Restricted tunable in AIX 6.1 |
|
no |
icmpaddresmask |
0 |
0 |
0 |
Disable Internet Control Message Protocol (ICMP) query message. No change in value from AIX 5.3. |
|
no |
ip6srcrouteforward |
0 |
1 |
0 |
IPv6 source forwarding is disabled. |
|
no |
ipforwarding |
0 |
0 |
0 |
No change from AIX 5.3 recommendation.Kernel does not involve in IP forwarding. |
|
no |
ipignoreredirects |
1 |
0 |
1 |
Used to control ICMP redirects and setting it to 1 ensures that malicious ICMP request cannot be used to create manipulated routes. |
|
no |
ipqmaxlen1 |
250 |
100 |
250 |
Default will not handle large workloads. Hence increased to 250. |
|
no |
ipsendredirects |
0 |
1 |
0 |
Default will not handle large workloads. Hence increased to 250. |
|
no |
ipsrcrouteforward |
1 |
1 |
1 |
Source route forwarding is encouraged. |
|
no |
ipsrcrouterecv |
0 |
0 |
1 |
Source route forwarding is encouraged. |
|
no |
ipsrcroutesend |
1 |
1 |
1 |
No change in value from AIX 5.3. |
|
no |
nonlocsrcroute |
0 |
1 |
1 |
Source route encouraged |
|
no |
rfc1323 |
1 |
0 |
1 |
The rfc1323 tunable enables the TCP window scaling option. |
|
no |
sb_max |
1310720 |
1048576 |
1048576 |
Number of socket buffer queued with each sockets. More socket buffer space provided compared with AIX 5.3. |
|
no |
tcp_mssdflt |
|
1460 |
1460 |
Segment size used in communicating with remote networks. |
|
no |
tcp_nagle_limit |
1 |
65535 |
1 |
DB2 already disable this per connection. This tunable will ensure AIX does not try to consolidate packets. |
|
no |
tcp_nodelayack |
1 |
0 |
1 |
Does not want to delay the ACK. |
|
no |
tcp_pmtu_discover |
0 |
1 |
0 |
We recommend 0 to prevent illegal access through source routing. |
|
no |
tcp_recvspace |
262144 |
16384 |
262144 |
The tcp_recvspace tunable specifies how many bytes of data the receiving system can buffer in the kernel on the receiving sockets queue. This can also be set through DB2 overrides. |
|
no |
tcp_sendspace |
262144 |
16384 |
262144 |
The tcp_sendspace tunable specifies how much data the sending application can buffer in the kernel before the application is blocked on a send call. This can also be set through DB2 overrides. |
|
no |
tcp_tcpsecure3 |
|
0 |
5 |
|
|
no |
use_isno4 |
0 |
1 |
1 |
Restricted tunable in AIX 6.1. |
|
vmo |
cpu_scale_memp |
8 |
8 |
8 |
Restricted tunable in AIX 6.1. |
|
vmo |
page_steal_method |
0 |
1 |
1 |
Restricted tunable in AIX6.1 |
|
vmo |
lru_file_repage |
1 |
0 |
0 |
Restricted tunable in AIX 6.1. |
|
vmo |
maxclient% |
80 |
90 |
90 |
Restricted tunable in AIX 6.1. |
|
vmo |
maxfree |
minfree+512 |
1088 |
minfree+512 |
Difference between minfree and maxfree must not be more than 1000 |
|
vmo |
maxperm% |
80 |
90 |
90 |
Restricted tunable in AIX 6.1. |
|
vmo |
memory_affinity |
1 |
1 |
1 |
Restricted tunable in AIX 6.1. |
|
vmo |
minfree |
4096 [memory less than 8 GB] 8192 [memory greater than 8 GB |
960 |
4096 |
It is at least the size of minimum page read ahead value. |
|
vmo |
minperm% |
20 |
3 |
3 |
Set to low value to avoid computational pages to be paged. |
|
vmo |
strict_maxclient |
0 |
1 |
1 |
Restricted tunable in AIX 6.1. |
以上内容摘自 Best Practices for DB2 on AIX 6.1 for POWER Systems 文档