This guide will assist you in setting up an rsnapshot backup server on your network. rsnapshot uses rsync via ssh to perform unattended backups of multiple systems in your network. The guide can be found on the centos website here.
In this article Barry Mavin, CEO and Chief Software Architect for Recital provides details on how the Recital Database Server can be used to provide a solution for Universal Data Integration.
Overview
The Recital Database Server handles universal cross-platform data access to a wide range of data sources. The database server natively handles full remote SQL data access to Recital, Visual FoxPro, FoxPro, FoxBASE, Clipper and older dBase data. Using Bridges, it handles full remote SQL data access to C-ISAM and OpenVMS RMS. Using gateway connections, it handles full remote SQL data access to Oracle, MySQL, PostgreSQL, SQL Server, server-side ODBC, server-side JDBC and server-side OLE DB data sources. With its ability to access data using server-side ODBC, JDBC and OLE DB drivers from clients on all supported operating systems (Windows, Linux, Unix, OpenVMS), the Recital Database Server is an ideal Data Integration Solution for applications of all sizes and complexity.
Universal Data Integration Solutions
There are several ways in which data may be accessed by the Database Server.
Table 1:
Client Universal Data Access solutions for accessing local or remote data.
| Client | Solution |
|---|---|
| Recital | Use remote gateway connections |
| Visual FoxPro | Use the Universal ODBC Driver |
| Java (all platforms) | Use the Universal JDBC Driver |
| .NET Framework | Use the Universal .NET Data Provider |
| Microsoft Office | Use the Universal ODBC Driver |
| Windows Mobile | Use the Universal Compact Framework .NET Data Provider |
| PHP on Linux | Use the Universal ODBC Driver for Linux |
| Mono on Linux | Use the Universal .NET Data Provider |
| Others | If the data source you want to access is not in the list above, then you can use a remote ODBC, JDBC or OLE DB gateway. You can find examples of connection strings for most ODBC and OLE DB data sources by clicking here. |
Table 2:
Windows Server Universal Data Access solutions accessible from any remote client running on Windows, Linux, Unix or OpenVMS:
| Data Source | Solution |
|---|---|
| Recital | Native support (See table 1) |
| Visual FoxPro | Native support (See table 1) |
| FoxPro | Native support (See table 1) |
| FoxBASE | Native support (See table 1) |
| Clipper | Native support (See table 1) |
| dBase | Native support (See table 1) |
| C-ISAM | Use a bridge (See table 1) |
| Access | Use a gateway connection gateway="oledb:Provider=Microsoft.Jet.OLEDB.4.0;Data Source=\somepath\mydb.mdb;User Id=admin;Password=;" |
| Exchange | Use a gateway connection gateway="oledb:Provider=ExOLEDB.DataSource;Data Source=http://servername/publicstore" |
| Excel | Use a gateway connection gateway="oledb:Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\MyExcel.xls;" |
| Oracle | Use a gateway connection gateway="oledb:Provider=msdaora;Data Source=TheOracleDB;User Id=xxxxx;Password=xxxxx;" |
| SQL Server | Use a gateway connection gateway="oledb:Provider=sqloledb;Data Source=Aron1;Initial Catalog=pubs;User Id=sa;Password=asdasd;" |
| MySQL | Use a gateway connection gateway="oledb:Provider=MySQLProv;Data Source=mydb;User Id=xxxxx;Password=xxxxx;" |
| IBM DB2 | Use a gateway connection gateway="oledb:Provider=DB2OLEDB;Network Transport Library=TCPIP;Network Address=XXX.XXX.XXX.XXX;Initial Catalog=MyCtlg;Package Collection=MyPkgCol;Default Schema=Schema;User ID=MyUser;Password=MyPW" |
| Sybase ASA | Use a gateway connection gateway="oledb:Provider=ASAProv;Data source=myASA" |
| Sybase ASE | Use a gateway connection gateway="oledb:Provider=Sybase.ASEOLEDBProvider;Srvr=myASEserver,5000;Catalog=myDBname;User Id=username;Password=password" |
| IBM Informix | Use a gateway connection gateway="oledb:Provider=Ifxoledbc.2;password=myPw;User ID=myUser;Data Source=dbName@serverName;Persist Security Info=true" |
| Ingres | Use a gateway connection gateway="odbc:dsn=data_source_name" |
| Firebird | Use a gateway connection gateway="odbc:dsn=data_source_name" |
| IBM AS400 iSeries | Use a gateway connection gateway="oledb:PROVIDER=IBMDA400; DATA SOURCE=MY_SYSTEM_NAME;USER ID=myUserName;PASSWORD=myPwd" |
| Interbase | Use a gateway connection gateway="oledb:provider=sibprovider;location=localhost:;data source=c:\databases\gdbs\mygdb.gdb;user id=xxxxx;password=xxxxx" |
| Others |
If the data source you want to access is not in the list above, then you can use server-side ODBC, JDBC or OLE DB. |
Table 3:
Linux and Unix Server Universal Data Access solutions accessible from any remote client running on Windows, Linux, Unix or OpenVMS:
| Data Source | Solution |
|---|---|
| Recital | Native support (See table 1) |
| Visual FoxPro | Native support (See table 1) |
| FoxPro | Native support (See table 1) |
| FoxBASE | Native support (See table 1) |
| Clipper | Native support (See table 1) |
| dBase | Native support (See table 1) |
| C-ISAM | Use a bridge (See table 1) |
| Oracle | Use a gateway connection gateway="oracle:Connection_String" |
| MySQL | Use a gateway connection gateway="mysql:Connection_String" |
| IBM DB2 | Use a gateway connection gateway="db2:Connection_String" |
| PostgreSQL | Use a gateway connection gateway="postgres:Connection_String" |
| Others |
If the data source you want to access is not in the list above, then you can use a server-side JDBC driver. |
Table 4:
OpenVMS Server Universal Data Access solutions accessible from any remote client running on Windows, Linux, Unix or OpenVMS:
| Data Source | Solution |
|---|---|
| Recital | Native support (See table 1) |
| Visual FoxPro | Native support (See table 1) |
| FoxPro | Native support (See table 1) |
| FoxBASE | Native support (See table 1) |
| Clipper | Native support (See table 1) |
| dBase | Native support (See table 1) |
| RMS | Use a bridge (See table 1) |
| Others |
If the data source you want to access is not in the list above, then you can use a server-side JDBC driver. |
Supported Data Sources
Native Data Access
The Recital Database Server has native built-in support for the following data sources:
- Recital
- Visual FoxPro
- FoxPro
- FoxBASE
- Clipper
- dBase
You can setup tables to work with using the Database Administration Tool in Recital Enterprise Studio.
Bridges
Using Bridges, you can access the following data sources as if they were standard Recital/FoxPro tables:
- CISAM
- OpenVMS RMS
You can setup bridges using the Database Administration Tool in Recital Enterprise Studio.
Gateways/Connections
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)
- OLEDB Use this to connect to SQL Server and other Windows OLE DB data sources)
- MySQL
- PostgreSQL
Remote Data Object functions
Recital 10 includes a complete and robust set of data source independent functions for accession MySQL, Oracle, DB2 and Postgres. This article explains how to use them.
Client Data Access drivers
Included with the Recital Database Server are three Client drivers. These Client drivers can access any data sources supported by the Recital Database Server. They are not restricted to accessing only Recital data. They can be used to access server-side ODBC, JDBC and OLE DB data sources also.
Recital Universal .NET Data Provider
Use this client driver when building .NET applications with Visual Studio .NET. A data provider in the .NET Framework serves as a bridge between an application and a data source. A data provider is used to retrieve data from a data source and to reconcile changes to that data back to the data source.
Key features of the Recital Universal .NET Data Provider:
- Fully Internet enabled
The Recital Universal .NET Data Provider works across the internet providing access to a wide range of data sources located on remote servers running Windows, Linux, Unix and OpenVMS. - SQL Server compatible
The Recital Universal .NET Data Provider is plug compatible with the .NET Framework SQL Server Data Provider. - Cross-platform Data Integration
Using the Recital Universal .NET Data Provider, you can connect to remote Windows, Linux, Unix or OpenVMS servers and access any data source supported by the Recital Database Server. - Managed code
The Recital Universal .NET Data Adaptor written in C# is 100% .NET Framework managed code. - Runs on Windows Mobile
The Recital Universal .NET Data Adaptor runs under the .NET Compact Framework on Windows Mobile.
Recital Universal JDBC Driver
The JDBC API is the industry standard for database-independent connectivity between the Java programming language and a wide range of databases. The JDBC API provides a call-level API for SQL-based database access. JDBC technology allows you to use the Java programming language to exploit "Write Once, Run Anywhere" capabilities for applications that require access to enterprise data.
Key features of the Recital Universal JDBC Driver:
- Fully Internet enabled
The Recital Universal JDBC driver works across the internet providing access to a wide range of data sources located on remote servers running Windows, Linux, Unix and OpenVMS. - JDBC 3.0 API
The Recital Universal JDBC driver supports the JDBC 3.0 API. - Pure Java Type 3 Driver
The Recital Universal JDBC driver is a 100% pure Java Type 3 driver. - Full Access to Metadata
The JDBC API provides metadata access that enables the development of sophisticated applications that need to understand the underlying facilities and capabilities of a specific database connection. - Cross-platform Data Integration
Using the Recital Universal JDBC driver, you can connect to remote Windows, Linux, Unix or OpenVMS servers and access any data source supported by the Recital Database Server. - No Installation
A pure JDBC technology-based driver does not require special installation; it is automatically downloaded as part of the applet that makes the JDBC calls. The Recital Universal JDBC Driver is 100% java.
Recital Universal ODBC Driver
Connect to remote data from Microsoft Office or other applications that support ODBC data access. The Recital Universal ODBC Driver is also available for Linux and Unix.
Key features of the Recital Universal ODBC Driver:
- Fully Internet enabled
The Recital Universal ODBC driver works across the internet providing access to a wide range of data sources located on remote servers running Windows, Linux, Unix and OpenVMS. - Works with Crystal Reports
The Recital Universal ODBC driver supports the SQL syntax generated by Crystal Reports. - Works with Microsoft Office
The Recital Universal ODBC driver works with Microsoft Office products. - Works with PHP on Linux
The Recital Universal ODBC driver is available for Linux and works with PHP.
Many motherboards nowadays have integrated gigabit ethernet that use the Realtek NIC chipset.
The Realtek r8168B network card does not work out of the box in Redhat/Centos 5.3: instead of loading the r8168 driver, modprobe loads the r8169 driver, which is broken as can be seen with ifconfig which shows large amounts of dropped packets. A solution is to download the r8168 driver from the Realtek website and install it using the following steps:
Check whether the built-in driver, r8169.ko (or r8169.o for kernel 2.4.x), is installed.
# lsmod | grep r8169
If it is installed remove it.
# rmmod r8169
Download the R8168B linux driver from here into /root.
Unpack the tarball :
# cd /root
# tar vjxf r8168-8.012.00.tar.bz2
Change to the directory:
# cd r8168-8.012.00
If you are running the target kernel, then you should be able to do :
# make clean modules
# make install
# depmod -a
# insmod ./src/r8168.ko (or r8168.o in linux kernel 2.4.x)
make sure modprobe knows not to use r8169, and that depmod doesn’t find the r8169 module.
# echo "blacklist r8169" >> /etc/modprobe.d/blacklist
# mv /lib/modules/`uname -r`/kernel/drivers/net/r8169.ko \ /lib/modules/`uname -r`/kernel/drivers/net/r8169.ko.bak
You can check whether the driver is loaded by using the following commands.
# lsmod | grep r8168
# ifconfig -a
If there is a device name, ethX, shown on the monitor, the linux driver is loaded. Then, you can use the following command to activate it.
# ifconfig ethX up
After this you should not see any more dropped packets reported.
Recital is a rich and versatile product with many ways to do the same thing. Developers usually write code in the way that they are accustomed to without paying much attention to how this will perform in a multi-user environment with large amounts of users and transactions. The best way to optimize Recital applications is to use the built-in tuning capabilities introduced in Recital 10.
Specifying this seems to reslove the problem:
-Xmx512m -XX:MaxPermSize=512m
try
open database southwind
catch
die("Cannot open database, please try later.")
endtry
SE Linux is a feature of the Linux kernel that provides mandatory access control. This policy based access control system grants far greater control over the resources on a machine than standard Linux access controls such as permissions.
Many modern Linux distributions are shipping with SELinux enabled by default, Fedora 14 and Rhel 6 both install with it enabled.
When you run Recital Web on a SELinux enabled machine and navigate to the default.rsp page you will see something similar to the screen shot below.
If you launch the SELinux troubleshooter you will see the following problem.
SELinux is blocking the apache server from accessing the Recital server running on port 8001.
To manage you SELinux policy you must have the policycoreutils package group installed. The policycoreutils contains the policy core utilities that are required for basic operation of a SELinux system.
If you wish to use a GUI tool, you must install the policycoreutils-gui package.
At the command prompt execute the following:
As root
$ yum install policycoreutils
$ semanage port -a -t http_port_t -p tcp 8001
$ service recital restart
$ service httpd restart
We use the semanage command here to allow the http server access to port 8001. Once you have completed the steps detailed above you can go and navigate back to the default.rsp page in your borwser, where you will find the permission denied message is now replaced by the default.rsp page.
SELinux does a great job of restricting services and daemons so rather than simply disabling it, why not work with it!
When it comes to security, every little bit helps...
If you are using the Oracle Gateway in Recital, make sure the Oracle environment (ORACLE_HOME, ORACLE_SID etc.) is set up before starting the Recital Server. If not, you will see the error ORA-01019. A call to the Oracle environment setup script can be added to the /etc/init.d/recital script if your Recital Server is set to run on startup.
Ext3 commits writes to disk within approximately 5 seconds - Ext4 can take from 40-150 seconds. In addition, if a system is using Ext3 and crashes before the commit takes place you will still have the previous contents of a file where under Ext4 the file will be empty. Theodore Tso feels that this is a failure at the application level and that the file system is behaving as designed and as specified by the POSIX spec (which apparently does not specify what is supposed to happen when a system is not shut down cleanly). His solution to the issue is to suggest proper use of fsync() and lists various scenarios/examples in post 54 of the bug report (linked above). In addition he wrote a patch that recognize the rename() situation mentioned in his post 54 yet retains the normal Ext4 behaviors and performance in the majority of cases. Also a more "proper" solution has been provided which allows the behavior of Ext3 to be retained under Ext4 by mounting it with alloc_on_commit.
A somewhat related topic is the use of on-board caching by hard drives. This behavior can be modified on most drives by using hdparm.
[data] oplocks = False level2 oplocks = False
veto oplock files = /*.dbf/*.DBF/*.ndx/*.NDX/*.dbx/*.DBX/*.dbt/*.DBT/
You can further tune samba by following this guide.
mount -t cifs {mount-point} -o username=name,pass=pass,directio
The directio option is used to not do inode data caching on files opened on this mount. This precludes mmaping files on this mount. In some cases with fast networks and little or no caching benefits on the client (e.g. when the application is doing large sequential reads bigger than page size without rereading the same data) this can provide better performance than the default behavior which caches reads (readahead) and writes (writebehind) through the local Linux client pagecache if oplock (caching token) is granted and held. Note that direct allows write operations larger than page size to be sent to the server.
Apr 22 16:57:39 bailey kernel: Status code returned 0xc000006d NT_STATUS_LOGON_FAILURE Apr 22 16:57:39 bailey kernel: CIFS VFS: Send error in SessSetup = -13 Apr 22 16:57:39 bailey kernel: CIFS VFS: cifs_mount failed w/return code = -13The you need to create the Samba user specified on the mount command
smbpasswd -a usernameFYI - Make sure you umount all the Samba {mount-point(s)} before shutting down Samba.