GUÍA PARA LA ELABORACIÓN DEL PLAN DE FORMACIÓN

There are three main ways to look at RSS:

򐂰 The onstat command

򐂰 The sysmaster database

5.6.1 onstat -g rss

The onstat -g rss command can be run on the Primary and any RSS server. Figure 5-5 shows a sample run on a Primary.

Figure 5-5 onstat -g rss run on the Primary

When performed remotely, the following information is available:

򐂰 The type of instance. This instance is also a Primary in an HDR pair. 򐂰 Index Page Logging status is enabled, and it shows when it was enabled. 򐂰 It tells the number of RSS servers.

򐂰 Lastly, it gives information about the state of those two Secondary servers. Figure 5-6 shows a sample run of onstat -g rss on a RSS server.

Figure 5-6 onstat -g rss on a RSS server

$ onstat –g rss rss2

IBM Informix Dynamic Server Version 11.10.FC1 -- On-Line (Prim) -- Up 01:07: 48 -- 52224 Kbytes

RSS Server control block: 0x0 RSS server name: rss2 RSS server status: Defined RSS connection status: Inactive Next log page to send( log id.page): 0.0 Sequence number of next buffer to send: 0 Sequence number of last buffer acked: 0 Log Pages Snooped:

RSS Srv From From Tossed name Cache Disk (LBC full)

IBM Informix Dynamic Server Version 11.10.FC1 -- Read-Only RSS -- Up 00:00 :22 -- 60416 Kbytes

Local server type: RSS Server status: Active Source server name: primary Connection status: Connected

Last log page received( log id.page): 10.37 $

Notice the fact that no mention is made of Index Page Logging. This is because it is irrelevant on a Secondary. Only how the Primary sends the pages is

considered important.

5.6.2 onstat -g rss verbose

It is possible to get even more information from onstat with the onstat -g rss verbose option. This is depicted in a snippet shown in Figure 5-7.

Figure 5-7 onstat -g rss verbose

Note: The verbose output will print this detailed information for all

secondaries.

IBM Informix Dynamic Server Version 11.10.FC1 -- On-Line (Prim) -- Up 00:11: 37 -- 52224 Kbytes

Local server type: HDR Primary Index page logging status: Enabled

Index page logging was enabled at: 2007/07/24 12:31:19 Number of RSS servers: 2

RSS Server information:

RSS Server control block: 0x10c9174a8 RSS server name: rss_node

RSS server status: Active RSS connection status: Connected Log transmission status: Active Next log page to send( log id.page): 10.39 Sequence number of next buffer to send: 5 Sequence number of last buffer acked: 0

As an alternative, use the onstat -g rss <secserver> command to get detailed information for just one Secondary. Figure 5-8 shows a sample run of this command.

Figure 5-8 Output of onstat -g rss asking for more details on a single Secondary

5.6.3 onstat -g smx

The onstat -g smx command prints server multiplexer group information for servers using SMX.

For each server it will show such information as:

򐂰 The INFORMIXSERVER name

򐂰 The address in shared memory of the SMX pipe

򐂰 The encryption status

򐂰 The number of bytes sent and received 򐂰 The number of buffers sent and received 򐂰 The number of write and read calls 򐂰 The number of retries

$ onstat –g rss rss2

IBM Informix Dynamic Server Version 11.10.FC1 -- On-Line (Prim) -- Up 01:07: 48 -- 52224 Kbytes

RSS Server control block: 0x0 RSS server name: rss2 RSS server status: Defined RSS connection status: Defined Log transmission status: Inactive Next log page to send( log id.page): 0.0 Sequence number of next buffer to send: 0 Sequence number of last buffer acked: 0 Log Pages Snooped:

RSS Srv From From Tossed

5.6.4 onstat -g smx ses

The onstat -g smx ses command will first print out the address in shared memory for the SMX control block. Then it will print a line for every server with the following information:

򐂰 The INFORMIXSERVER.

򐂰 The address in shared memory of the SMX session.

򐂰 The type of connection. For RSS servers, this will typically say “RSS Send.” 򐂰 The number of reads and writes.

5.6.5 The sysmaster database

Alternatively, the sysmaster database can be used to retrieve this information.

syssmx

The syssmx table contains information about the SMX session. An SMX session is simply the handling of communications with the other servers connected in either RSS or SDS environments

Table 5-1 illustrates the meaning of the rows in that table.

Table 5-1 The syssmx table in sysmaster

Column Meaning

address The address in shared memory of the smx pipe for that connection

name The name of the connection

encryption_status Whether encryption is turned on or not buffers_sent The number of buffers sent across the

smx layer

buffers_recv The number of buffers received across the smx layer

bytes_sent The number of bytes sent across the smx layer

bytes_recv The number of bytes received across the smx layer

5.6.6 Event alarms

The database server uses the event-alarm feature to report a situation that requires the immediate attention of a database administrator. To use the event-alarm feature, set the ALARMPROGRAM configuration parameter to the full path name of an executable file that performs the necessary administrative actions. A simple example would be a shell script that informs the database administrator about the event either through e-mail or pager.

The database administrator can also monitor the event alarms that are triggered for the RSS servers. When each event alarm is triggered, the Primary server writes a message to the message log that includes RSS server name. There are several situations when the Primary server triggers event alarms for RSS. The most important ones that needs to be monitored are:

򐂰 RSS log replay position is falling too far behind the RSS source.

This message displays when the log replay position for the RSS server is falling too far behind the Primary. If this trend continues, the Primary might not have a logical log file available when the RSS server requests it.

򐂰 RSS server is not acknowledging log transmissions.

If the Primary server does not get acknowledgement (ACK) back (after it reaches the limit of successful transmissions) due to a network issue, it will trigger this event alarm. The Primary server will not send any more logical log pages until an acknowledgement is received.

򐂰 Error receiving a buffer from RSS server.

The Primary server experienced an error receiving a message from the RSS server.