HOWTO: Backup up a live linux site running vmware virtual machines

If you have a live linux site that is running vmware virtual machines, you can pause the virtual machines when you want to perform a backup, I use acronis for linux which does incremental backups and you can specify a command to run before and after the backup, this allows backups to be performed at scheduled times daily without any intervention. In my examples below, the virtual machine i want to control is in /root/vmware/Recital/Recital.vmx

To pause the virtual machine on linux:

# vmrun pause /root/vmware/Recital/Recital.vmx

and then to unpause after the backup has completed:

# vmrun unpause /root/vmware/Recital/Recital.vmx

That is basicallty it, no need to attend the backup and it can be perfomed at a suitable time so no users are affected.

Incidentally, vmrun lets you startup a virtual machine at system startup too, without needing the GUI:

# vmrun start /root/vmware/Recital/Recital.vmx

Or alternatively stop it:

# vmrun stop /root/vmware/Recital/Recital.vmx

There are lots of other capabilities of this command, running applications inside the virtual machine etc etc. For full details just type vmrun in a terminal window.

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10.0.1 patch enhancements

I Just added a few new functions to the latest 10.0.1 patch release which should be generally available next week.

New MD5( expC ) function to calculate an MD5 crypto key from any character expression
New MD5FILE( expC ) function calculates an MD5 crypto key for a given filename. If the filename is a pattern e.g *.* it will calculate the key across all files matching the pattern
New mod_recital.so available for using Recital Web on linux x86_32
New mod_recital64.so available for using Recital Web on linux x86_64

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How can I integrate external data in with Recital?

Recital provides a wide variety of connectivity solutions to external data sources. This article provides an overview.

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Understanding Recital Logging

This article talks about the log files available in Recital products and how to enable logging when required.

Overview

When discussing a problem with the Recital Support Team, one of the most common requests is that you enable logging and send them the log files produced. Log files along with error files are designed to provide detailed information about Recital processes and the prevailing environment and can be a fast-track to resolving a problem.

Log Files

There are three main types of log file:

System Log
Client/Server Communication Logs
Custom Logs

System Log

The System log is a system-wide all product log. It tracks all login and logout operations from either Recital or the Recital Server. Logout details include the exit code: 0 for an error-free, 'normal' exit and the error number and message when an error has occurred. It also shows the licenses that have been loaded and any license error codes and messages. The system log filename is recital.log.

Client/Server Communication Logs

The Client/Server communication logs track the requests and responses between the Recital Server and its clients. The log files are as follows:

Filename	Type	Description
dbserver.log	System-wide	The Recital Server startup log. This logs any problems with the Recital Server startup.
port.log	System-wide	The port listener log. The port listener (or portserver) listens on port 8001 for client connection requests and spawns the appropriate server process.
net.log	Connection	The netserver log. The netserver is the Recital Server database and 4GL engine.
rsi.log	Connection	The Recital Server Interface (RSI) Gateway log. This logs communication with the Database Gateways to SQL databases.
rec.log	Connection	The Recital Database Gateway log. The Recital Database Gateway (or recserver) is the SQL database engine for Recital Gateway data access.
mys.log	Connection	The MySQL Database Gateway log.
ora.log	Connection	The Oracle Database Gateway log.
inf.log	Connection	The Informix Database Gateway log.
ing.log	Connection	The Ingres Database Gateway log.
pos.log	Connection	The PostgreSQL Database Gateway log.
jdb.log	Connection	The JDBC Driver Database Gateway log.

Custom Logs

The Recital/4GL USERLOG() function can be used to log information to a user-specific log file for debugging or audit trail purposes. For full information on this function, please see the USERLOG() documentation.

Enabling Log Files

For instructions on enabling log files for individual products, please follow these links:

Recital Server for Windows
Recital Server for Linux
Recital Server for UNIX
Recital Server for OpenVMS
Recital for Linux
Recital for UNIX
Recital for OpenVMS

Enabling Log Files: Recital Server for Windows

To enable the system log file for the Recital Universal Application Server for Windows, include the following command in the UAS\config.db file:

set syslogging on

The Recital Server Manager System Logging tab allows for the viewing and resetting of the System log.

Section

Item

Description

System Logging

DateTime

Date and time stamp of the action.

Name

Action

Action logged: Login, Logoff, Errot

Details

Details of action

Buttons

Purge

Allows the log file to be reset

Refresh

Refreshes the display

To set up Client/Server logging, use the Recital Server Manager Settings tab to update the server's Registry entries:

The following Log file settings can be configured:

Item	Description
Log files Directory Path	Enter the directory in which log files will be created. The default is the UAS\log directory.
Enabled	Check to enable log file creation.
Versions	Check to enable log file versioning.
Listener	Click to view the current port listener log file
Server	Click to view the current netserver log file
Purge	Click to purge all log files

Enabling Log Files: Recital Server for Linux

To enable the system log file for the Recital Server for Linux, include the following command in the conf/config.db file:

set syslogging on

To set up Client/Server logging, the Recital Server can be started with the 'logging' parameter, in which case, all relevant logging will take place.

# service startup logging<

Alternatively, one or more of the following environment variables can be added to the dbserver.conf file or set at the Operating System prompt. The Recital Server must be restarted before environment variable changes will be recognized. Each environment variable should be set to the name of a log file.

Environment Variable

Logs Activity of...

UASLOG_PORT

Port Server (db_rsiserver)

UASLOG_NET

(Net) Server (db_netserver)

UASLOG_ORA

Oracle Server (db_oraserver)

UASLOG_INF

Informix Server (db_infserver)

UASLOG_ING

Ingres Server (db_ingserver)

UASLOG_JDB

JDBC Server (db_jdbserver)

UASLOG_REC

Recital Server (db_recserver)

Extract from recital.conf:

UASLOG_PORT="port.log" ; export UASLOG_PORT
UASLOG_NET="net.log"   ; export UASLOG_NET
UASLOG_ORA="ora.log"  ; export UASLOG_ORA
UASLOG_INF="inf.log"     ; export UASLOG_INF
UASLOG_ING="ing.log"   ; export UASLOG_ING
UASLOG_JDB="jdb.log"   ; export UASLOG_JDB
UASLOG_REC="rec.log"   ; export UASLOG_REC

DB_LOGDIR

If the environment variable DB_LOGDIR is set to an existing directory, all log files will be written to this directory. If not, the log files will be created in the bin directory.

DB_LOGDIR is set in the conf/recital.conf file. By default it is set to the log directory:

DB_LOGDIR=${ROI_ROOT}log/           ; export DB_LOGDIR

DB_LOGVER

If the environment variable DB_LOGVER is greater than 0, version numbers are added to the file names. For example, the activity of the first Net Server process will be logged to net.log, the second to net001.log, the third to net002.log etc. up to the maximum value of DB_LOGVER.

DB_LOGVER is set in the conf/recital.conf file:

DB_LOGVER=10; export DB_LOGVER

Enabling Log Files: Recital Server for UNIX

To enable the system log file for the Recital Server for UNIX, include the following command in the conf/config.db file:

set syslogging on

To set up Client/Server logging, the Recital Server can be started with the 'logging' parameter, in which case, all relevant logging will take place.

# service startup logging

Alternatively, one or more of the following environment variables can be added to the <em>dbserver.conf</em> file or set at the Operating System prompt. The Recital Server must be restarted before environment variable changes will be recognized. Each environment variable should be set to the name of a log file.

Environment Variable

Logs Activity of...

UASLOG_PORT

Port Server (db_rsiserver)

UASLOG_NET

(Net) Server (db_netserver)

UASLOG_ORA

Oracle Server (db_oraserver)

UASLOG_INF

Informix Server (db_infserver)

UASLOG_ING

Ingres Server (db_ingserver)

UASLOG_JDB

JDBC Server (db_jdbserver)

UASLOG_REC

Recital Server (db_recserver)

Extract from recital.conf:

UASLOG_PORT="port.log" ; export UASLOG_PORT
UASLOG_NET="net.log"   ; export UASLOG_NET
UASLOG_ORA="ora.log"  ; export UASLOG_ORA
UASLOG_INF="inf.log"     ; export UASLOG_INF
UASLOG_ING="ing.log"   ; export UASLOG_ING
UASLOG_JDB="jdb.log"   ; export UASLOG_JDB
UASLOG_REC="rec.log"   ; export UASLOG_REC

DB_LOGDIR

If the environment variable DB_LOGDIR is set to an existing directory, all log files will be written to this directory. If not, the log files will be created in the bin directory.

DB_LOGDIR is set in the conf/recital.conf file. By default it is set to the log directory:

DB_LOGDIR=${DB_ROOT}log/           ; export DB_LOGDIR

DB_LOGVER

DB_LOGVER is set in the conf/recital.conf file:

DB_LOGVER=10; export DB_LOGVER

Enabling Log Files: Recital Universal Application Server for OpenVMS

To enable the system log file for the Recital Universal Application Server for OpenVMS, include the following command in the db_uas:config.db file:

set syslogging on

To set up Client/Server logging, one or more of the following symbols can be added to the <em>db_uas:login.com</em> file. The Recital Server must be restarted before symbol changes will be recognized. Each symbol should be set to the name of a log file.

Symbol

Logs Activity of…

UASLOG_PORT

Port Server (db_rsiserver)

UASLOG_NET

(Net) Server (db_netserver)

UASLOG_ORA

Oracle Server (db_oraserver)

UASLOG_INF

Informix Server (db_infserver)

UASLOG_ING

Ingres Server (db_ingserver)

UASLOG_JDB

JDBC Server (db_jdbserver)

UASLOG_REC

Recital Server (db_recserver)

Extract from db_uas:login.com

$ uaslog_port :==  port.log
$ uaslog_net  :==  net.log
$ uaslog_ora  :==  ora.log
$ uaslog_inf  :==  inf.log
$ uaslog_ing  :==  ing.log
$ uaslog_jdb  :==  jdb.log
$ uaslog_rec  :==  rec.log

DB_LOGDIR

If the symbol DB_LOGDIR is set to an existing directory, all log files will be written to this directory. If not, the log files will be created in the UAS directory.

DB_LOGDIR is set in the db_uas:login.com file. By default it is set to the UAS.log] directory:

$db_logdir    :== 'db_root'.log]               ! system logging directory

DB_LOGVER

If the symbol DB_LOGVER is enabled, version numbers are added to the file names. For example, the activity of the first Net Server process will be logged to net.log, the second to net001.log, the third to net002.log etc.

DB_LOGVER is set in the db_uas:login.com file:

$db_logver  :== true                           ! enable multiple log files

Enabling Log Files: Recital for Linux

To enable the system log file for Recital for Linux, include the following command in the conf/config.db file:

set syslogging on

Enabling Log Files: Recital for UNIX

To enable the system log file for Recital for UNIX, include the following command in the conf/config.db file:

set syslogging on

Enabling Log Files: Recital for OpenVMS

To enable the system log file for Recital for OpenVMS, include the following command in the db_ovd:config.db file:

set syslogging on

In Brief

Log files provide important information to aid problem resolution, but they are also an overhead, so logging should only be enabled when required, not in normal production operation.
The System log provides a system-wide view of logins, exits and error codes.
The System log can be viewed in table format via the SYSLOGGING System Table.
The System log is enabled using the SET SYSLOGGING ON Recital/4GL command in the conf/config.db file.
Client/Server logs provide detailed information on client/server requests and responses.
Client/Server logs are enabled using environment variables, symbols or Registry entries or by specifying the 'logging' parameter when starting the Recital Server.
The location of log files is determined by the DB_LOGDIR setting.
Versioning of log files is determined by the DB_LOGVER setting.

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Agile development in a globally distributed team

There is a good article here this describes agile software development techniques. This is what we have always been doing but it's nice to see it defined formally.

We use this technique ourselves on our development portal.

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TOOLS: Eclipse subversion plugin

Subclipse is an Eclipse Team Provider plug-in providing support for Subversion within the Eclipse IDE. This plugin is required in order to use the recital eclipse workspace.

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Using Recital with PHP

This article describes how to use Recital with PHP.

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Working with server-side OLE DB data sources

In this article Barry Mavin, CEO and Chief Software Architect for Recital, details how to use the Client Drivers provided with the Recital Database Server to work with local or remote server-side OLE DB data sources.

Overview

The Recital Universal .NET Data Provider provides connectivity to the Recital Database Server running on any supported platform (Windows, Linux, Unix, OpenVMS) using the RecitalConnection object.

The Recital Universal JDBC Driver provides the same functionality for java applications.

The Recital Universal ODBC Driver provides the same functionality for applications that use ODBC.

Each of the above Client Drivers use a connection string to describe connections parameters.

The basic format of a connection string consists of a series of keyword/value pairs separated by semicolons. The equal sign (=) connects each keyword and its value.

The following table lists the valid names for keyword/values.

Name	Default	Description
Data Source -or- Server -or- Nodename		The name or network address of the instance of the Recital Database Server which to connect to.
Directory		The target directory on the remote server where data to be accessed resides. This is ignored when a Database is specified.
Encrypt -or- Encryption	false	When true, DES3 encryption is used for all data sent between the client and server.
Initial Catalog -or- Database		The name of the database on the remote server.
Password -or- Pwd		The password used to authenticate access to the remote server.
User ID		The user name used to authenticate access to the remote server.
Connection Pooling -or- Pool	false	Enable connection pooling to the server. This provides for one connection to be shared.
Logging	false	Provides for the ability to log all server requests for debugging purposes
Rowid	true	When Rowid is true (the default) a column will be post-fixed to each SELECT query that is a unique row identifier. This is used to provide optimised UPDATE and DELETE operations. If you use the RecitalSqlGrid, RecitalSqlForm, or RecitalSqlGridForm components then this column is not visible but is used to handle updates to the underlying data source.
Logfile		The name of the logfile for logging
Gateway		Opens an SQL gateway(Connection) to a foreign SQL data source on the remote server. Using Gateways, you can transparently access the following local or remote data sources: Recital Oracle ODBC (Server-side ODBC data sources) JDBC (Server-side JDBC data sources) ADO (Use this to connect to SQL Server and other Native Windows OLEDB data sources) MySQL PostgreSQL The gateway can be specified in several formats: servertype@nodename:username/password-database e.g. oracle@nodename:username/password-database mysql@nodename:username/password-database postgresql@nodename:username/password-database -or- odbc:odbc_data_source_name_on_server oledb:oledb_connection_string_on_server jdbc:jdbc_driver_path_on_server;jdbc:Recital:args

To connect to a server-side OLE DB data source, you use the gateway=value key/value pair in the following way.

gateway=oledb:oledb_connection_string_on_server

Important
When specifying the connection string be sure to quote the gateway= with "...".

You can find examples of connection strings for most ODBC and OLE DB data sources by clicking here.

Example in C# using the Recital Universal .NET Data Provider:

////////////////////////////////////////////////////////////////////////
// include the references below
using System.Data;
using Recital.Data;
 
////////////////////////////////////////////////////////////////////////
// The following code example creates an instance of a DataAdapter that 
// uses a Connection to the Recital Database Server, and a gateway to
// the SQL server Northwind database. It then populates a DataTable 
// in a DataSet with the list of customers. The SQL statement and 
// Connection arguments passed to the DataAdapter constructor are used 
// to create the SelectCommand property of the DataAdapter.
public DataSet SelectCustomers()
{
	string gateway = "oledb:Provider=sqloledb;Initial Catalog=Northwind;
		Data Source=localhost;Integrated Security=SSPI";
	RecitalConnection swindConn = new 
		RecitalConnection("Data Source=localhost;gateway=\""+gateway+"\");
	RecitalCommand selectCMD = new 
		RecitalCommand("SELECT CustomerID, CompanyName FROM Customers", swindConn);
	selectCMD.CommandTimeout = 30;
	RecitalDataAdapter custDA = new RecitalDataAdapter();
	custDA.SelectCommand = selectCMD;
	swindConn.Open();
	DataSet custDS = new DataSet();
	custDA.Fill(custDS, "Customers");
	swindConn.Close();
	return custDS;
}

Example in Java using the Recital Universal JDBC Driver:

////////////////////////////////////////////////////////////////////////
// standard imports required by the JDBC driver
import java.sql.*;
import java.io.*;
import java.net.URL;
import java.math.BigDecimal;
import Recital.sql.*;
 
////////////////////////////////////////////////////////////////////////
// The following code example creates a Connection to the Recital 
// Database Server, and a gateway to the SQL server Northwind database. 
// It then retrieves all the customers.
public void SelectCustomers()
{
    // setup the Connection URL for JDBC
	String gateway = "oledb:Provider=sqloledb;Initial Catalog=Northwind;
		Data Source=localhost;Integrated Security=SSPI";
	String url = "jdbc:Recital:Data Source=localhost;gateway=\""+gateway+"\";
	// load the Recital Universal JDBC Driver
	new RecitalDriver();
 
	// create the connection
	Connection con = DriverManager.getConnection(url);
	// create the statement
	Statement stmt = con.createStatement();
	// perform the SQL query
	ResultSet rs = stmt.executeQuery("SELECT CustomerID, CompanyName FROM Customers");
	// fetch the data
	while (rs.next()) 
	{
		String CompanyID = rs.getString("CustomerID");
		String CompanyName = rs.getString("CompanyName");
		// do something with the data...
	}
    
	// Release the statement
	stmt.close();
	
	// Disconnect from the server
	con.close();
}

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Review of IBM System Storage DS3400 Express

Dave Michelle at ITPRO writes a good review of the DS3400 San here.

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Gigabit LAN performance on Linux

It would appear that gigabit LAN is not! In fact it often runs at the same speed as 100Mbps LAN. Let's look at why exactly.

After configuring your network you can use the ifconfig command to see what speeds the LAN is connected. Even though 1000Mbps is reported by the card, the reality is that the overall throughtput may well be ~100Mpbs. You can try copying a large file using scp to demonstrate this.

As it turns out, in order to use a gigabit LAN you need to use CAT6 cables. CAT5 and CAT5E are not good enough. End result, the ethernet cards throttle back the speed to reduce dropped packets and errors.

You can find a good article here titled Squeeze Your Gigabit NIC for Top Performance. After tuning up the TCP parameters i found that it made no dfifference. The principal reasons behind low gigabit ethernet performance can be summed up as follows.

Need to use CAT6 cables
Slow Disk speed
Limitations of the PCI bus which the gigabit ethernet cards use

You can get an idea about the disk speed using the hdparm command:

Display the disk partitions and choose the main linux partition which has the / filesystem.

# fdisk -l

Then get disk cache and disk read statistics:

# hdparm -Tt /dev/sda0

On my desktop system the sata disk perfomance is a limiting factor. These were the results:

/dev/sda1:
Timing cached reads: 9984 MB in 2.00 seconds = 4996.41 MB/sec
Timing buffered disk reads: 84 MB in 3.13 seconds = 58.49 MB/sec

Well, that equates to a raw disk read speed of 58.49 * 8 = 467Mbps which is half the speed of a gigabit LAN.

So.. NAS storage with lots of memory looks to be the way to go... If you use the right cables!

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Overview

Log Files

System Log

Client/Server Communication Logs

Custom Logs

Enabling Log Files

Enabling Log Files: Recital Server for Windows

Enabling Log Files: Recital Server for Linux

DB_LOGDIR

DB_LOGVER

Enabling Log Files: Recital Server for UNIX

DB_LOGDIR

DB_LOGVER

Enabling Log Files: Recital Universal Application Server for OpenVMS

DB_LOGDIR

DB_LOGVER

Enabling Log Files: Recital for Linux

Enabling Log Files: Recital for UNIX

Enabling Log Files: Recital for OpenVMS

In Brief

Overview

Example in C# using the Recital Universal .NET Data Provider:

Example in Java using the Recital Universal JDBC Driver:

More...

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