以用户informix登录后，通过运行命令onmonitor或使用文本编辑器修改$INFORMIXDIR/etc/$ONCONFIG文件两种方法来达到初始化数据库的目的。

下面只就onmonitor方式进行介绍。

首先，以informix登录，

$ onmonitor

敲“P” 进Parameters子菜单，再敲“I”进入INITALIZATION初始化屏幕，此屏幕的每回操作都会破坏性摧毁指定数据库中的数据，操作一定要慎重，如下：

INITIALIZATION: Make desired changes and press ESC to record changes.
Press Interrupt to abort changes. Press F2 or CTRL-F for field-level help.
DISK PARAMETERS
Page Size [ 2] Kbytes Mirror [N]
Tape Dev. [/dev/null ]
Block Size [ 16] Kbytes Total Tape Size [ 10240] Kbytes
Log Tape Dev. [/dev/null ]
Block Size [ 16] Kbytes Total Tape Size [ 10240] Kbytes
Stage Blob [ ]
Root Name [rootdbs ] Root Size [ 200000] Kbytes
Primary Path [/usr/icbdb/rootdbs ]
Root Offset [ 0] Kbytes
Mirror Path [ ]
Mirror Offset [ 0] Kbytes
Phy. Log Size [ 3000] Kbytes Log. Log Size [ 1500] Kbytes
Number of Logical Logs [ 6]

确认以上输入无误后，键入ESC键，如果指定设备不存在或权限有问题，报错并会停在相应的位置上。对于操作系统文件形式的rootdbs时，如果该文件大小小于你设定的值，系统还会对相应文件进行初始化，使之达到所要求的空间。完成上属操作后，系统显示如下画面来设置共享内存。共享内存参数的修改可以多次进行，不会毁坏数据库的内容。

SHARED MEMORY: Make desired changes and press ESC to record changes.
Press Interrupt to abort changes. Press F2 or CTRL-F for field-level help.
SHARED MEMORY PARAMETERS
Server Number [ 0] Server Name [hbsave ]
Server Aliases [ ]
Dbspace Temp [ ]
Deadlock Timeout [ 60] Secs Number of Page Cleaners [ 1]
Forced Residency [N] Stack Size (K) [ 32]
Non Res. SegSize (K) [ 8000] Optical Cache Size (K) [ 0]

Dbspace Down Option [2]
Preserve Log For Log Backup [N]
Heterogeneous Commit [N] Transaction Timeout [ 300]
Physical Log Buffer Size [ 32] K Long TX HWM [ 50]
Logical Log Buffer Size [ 32] K Long TX HWM Exclusive [ 60]
Max # of Logical Logs [ 12] Index Page Fill Factor [ 90]
Max # of Locks [ 50000] Add SegSize (K) [ 8192]
Max # of Buffers [ 2000] Total Memory (K) [ 0]

Resident Shared Memory size [ 8818] Kbytes Page Size [ 2] Kbyte

键入ESC，完成共享内存参数修改，进入性能如下调整菜单，主要针对多CPU的机器设置虚拟机和设置NETTYPE：

PERFORMANCE: Make desired changes and press ESC to record changes.
Press Interrupt to abort changes. Press F2 or CTRL-F for field-level help.
PERFORMANCE TUNING PARAMETERS

Multiprocessor Machine [N] LRU Max Dirty [ 60]
Num Procs to Affinity [ 0] LRU Min Dirty [ 50]
Proc num to start with [ 0] Checkpoint Interval [ 300]
Num of Read Ahead Pages [ ]
CPU VPs [ 1] Read Ahead Threshold [ ]
AIO VPs [ ]
Single CPU VP [N] NETTYPE settings:
Use OS Time [N] Protocol Threads Users VP-class
Disable Priority Aging [N] [tlitcp] [ 2] [ 5] [CPU]
Off-Line Recovery Threads [ 10] [ ] [ ] [ ] [ ]
On-Line Recovery Threads [ 1] [ ] [ ] [ ] [ ]
Num of LRUS queues [ 8] [ ] [ ] [ ] [ ]


完成后键入ESC，进入数据复制设置画面：

DATA REPLICATION: Make desired changes and press ESC to record changes.
Press Interrupt to abort changes. Press F2 or CTRL-F for field-level help.
DATA REPLICATION PARAMETERS

Interval [ 30]
Timeout [ 30]
Auto [0]
Lost & Found [/usr/informix/etc/dr.lostfound ]

完成后键入ESC,显示如下：

DIAGNOSTICS: Make desired changes and press ESC to record changes.
Press Interrupt to abort changes. Press F2 or CTRL-F for field-level help.
DIAGNOSTIC PARAMETERS

Message Log [/usr/informix/online.log ]
Console Msgs. [/dev/console ]
Alarm Program [/usr/informix/log_full.sh ]

Dump Shared Memory [Y]
Dump Gcore [N]
Dump Core [N]
Dump Count [ 1]
Dump Directory [/tmp ]

进入设置PDQ菜单：

PDQ: Make desired changes and press ESC to record changes.
Press Interrupt to abort changes. Press F2 or CTRL-F for field-level help.
PARALLEL DATABASE QUERIES PARAMETERS

Max PDQ Priority [ 30]
Decision Support Queries [ ]
Decision Support Memory (Kbytes) [ ]
Maximum Decision Support Scans [ 1048576]
Dataskip [off ]
Optimizer Hint [2]