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Home -> Community -> Usenet -> c.d.o.server -> Re: NT vs Unix
DIFFERENCES BETWEEN ORACLE ON NT AND ORACLE ON UNIX
UNIX has been in existence since 1972: previous versions did exist, but they were written in PDP assembly language, rather than C. UNIX runs on most hardware architectures and versions are supplied by many vendors, most notably Sun, HP, IBM, Digital, Sequent, Data General, NCR and SCO.
2. SECURITY NT supports U.S. Department of Defense C2 security. This is likely to change, with more secure versions of NT becoming available.
Some specialised UNIX variants support B1 security.
3. USER INTERFACE NT has common graphical user interface across all architecture types. The interface changed between NT 3.51 and NT 4.0 from Windows 3.11 style to Windows 95 style.
Many UNIX versions have an X-Windows type of user interface, appearance varies between flavours. However, most UNIX commands are still character mode terminal based.
4. NUMBER OF DISK DRIVES NT limited to using drive letters A-Z.
UNIX has no built-in limitation on number of disk drives.
5. BACKGROUND PROCESSING AND BATCH JOBS NT only has AT command.
UNIX has more sophisticated job control mechanisms.
7. SCALEABILITY NT scales to about four CPUs, though major improvements to this may be expected in the next few years.
UNIX scales to at least 64 CPUs.
8. NUMBER OF SESSIONS NT supports only a single interactive GUI session, unless RAS or a third-party tool is used.
UNIX supports hundreds of interactive GUI or character mode sessions.
9. APPLICATION AVAILABILITY About 2,500 applications are available specifically for NT. It can also run many of the thousands of 16-bit Windows applications. Third-party products allow some UNIX applications to be run. Some public domain software is available.
There are about 10,000 UNIX applications available. Emulation software is available for many flavours of UNIX to allow some 16-bit Windows applications to be run. A large amount of public domain software is available.
Security
Once a user is connected to an NT server, they must then have access to a file to be able to access it.
NT can mount UNIX filesystems.
UNIX cannot mount NT NTFS filesystems.
NT files can only have a single name (unless using POSIX). Files on UNIX can have multiple names via hard or soft links.
Parallel Server has been available on UNIX since early Oracle7 releases. It is available on NT as of 7.3.3.
Each Oracle background process exists as a separate process on UNIX. The multi-threaded architecture is very efficient on NT, permitting fast, low-overhead context switches due to all threads sharing resources of the master process.
With multiple Oracle instances running on NT, there will be one ORACLE7X process per instance, each with multiple component threads.
UNIX Oracle7 ports have supported MTS since early 7.x releases.
Oracle registers each instance as a service to allow them to be started independent of a user logging on (e.g. instance started on machine boot). By default, services run as the SYSTEM user in NT. SYSTEM is not a user which can create a logon session - it is specifically for running system-orientated services. Oracle server processes on UNIX keep running even if no interactive users are logged on.
ORACLE_HOME and ORACLE_SID are variables defined in the NT Registry. The Oracle Installer and Oracle Instance Manager utilities define variables in the Registry as well as registering the Oracle instance as a service. You can edit the Registry manually via the Regedit.exe utility, but this is at your own risk. This will change the default values of the variables. They can also be changed on a per-session basis by entering:
C:\> set ORACLE_SID TEST
for example.
UNIX requires ORACLE_HOME and ORACLE_SID to be set in system or user login scripts. It is less easy for confusion to arise here, whereas on NT failure to set ORACLE_SID correctly (by inadvertently using the default setting in the Registry) may have disastrous results if a second instance opens a database which has already been opened by another instance.
The Event Viewer utility is how an NT administrator views system alert messages on NT. Oracle has integrated with Event Viewer such that Oracle startup/shutdown messages and the OS audit trail (if you configure OS auditing in Oracle) appear there. Performance Monitor is the NT equivalent of the UNIX sar command, providing detailed resource utilisation data for all processes running on the system.
Oracle has integrated with Performance Monitor such that you can view utilisation of operating system and Oracle resources (e.g. file write bytes per second - only those related to Oracle, library cache hit ratios, etc.). The Oracle7 Performance Monitor entry in the Start Menu | Programs | ORacle for Windows NT starts the standard NT Performance Monitor utility but feeds it Oracle-specific data.
The NT Performance Monitor and Event Viewer utilities can only "see"
one Oracle instance on NT. This is the one defined by the registry
entry:
HKEY_LOCAL_MACHINE/SOFTWARE/ORACLE/ORACLE_SID
So, although you can run multiple instances of Oracle on NT,
only the one identified by the ORACLE_SID value in the registry
will be visible to Performance Monitor and Event Viewer.
Oracle on UNIX provides no performance utilities for use at operating system level. Utilities such as sar or vmstat must be used to monitor Oracle background or shadow processes. These do not provide a graphical interface. More sophisticated third-party tools are available on UNIX.
Each raw partition will be assigned a drive letter but will not be formatted with a filesystem.
Similar to UNIX, each raw NT partition will be mapped to a single Oracle data, log or control file. Where NT differs from UNIX is the naming convention for these files. When referencing a raw partition in any Oracle SQL command, the syntax looks like this:
DATAFILE '\\.\f:' SIZE 49M REUSE
where f: is the drive letter assigned to the raw partition. Always make the Oracle file size 1M smaller than the raw partition size to avoid writing data to cylinder 0 of the disk.
Backup of a raw partition must be to a filesystem. The NT Backup utility can then be used to copy the backup to tape.
UNIX supports the use of raw partitions. Oracle can utilise this to provide better I/O performance.
The database password is defined during installation and by default is stored in hidden password file PWD<SID>.ora in the $ORACLE_HOME/database directory. However, you could get a similar effect to the UNIX DBA group by taking the following steps:
Then only users connected to the NT server in a group called DBA could CONNECT INTERNAL to Oracle and could do so without a password.
The NT feature to be aware of is that NT does not allow files in use to be copied, so you must use the OCOPY.EXE that Oracle provides to copy the database files to a staging location. From the staging location the files can be copied to the backup media, most likely a tape device. OCOPY cannot copy directly to tape devices, so a staging location is necessary.
Once the hot backup to disk with OCOPY is complete, you can use the NTBACKUP utility to back up to a SCSI tape.
20. IMPORT AND EXPORT
On NT, the largest value that can be used for RECORDLENGTH is 65,535,
which is the same as on UNIX. This is the value that will be used if
larger
values are specified.
--
Peter Teoh
Oracle Certified Professional
Received on Fri Jan 22 1999 - 21:50:53 CST
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