oraback.html

oracle数据库备份脚本

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<font face="Arial,Helvetica">Using these functions is very simple.&nbsp;
For example, to restart orasrv after an instance is restarted (with a script
called rc.orasrv.sh,) change the Poststart function to read:</font>
<p><font face="Arial,Helvetica">Poststart(){</font>
<br><font face="Arial,Helvetica">rc.orasrv.sh</font>
<br><font face="Arial,Helvetica">}</font>
<br>&nbsp;
<h2>
<font face="Arial,Helvetica">Deciding what or if to backup</font></h2>
<font face="Arial,Helvetica">Before actually running the backup, oraback.sh
checks oraback.conf to determine:</font>
<ul>
<li>
<font face="Arial,Helvetica">Whether the user running the backup is oracle,
or is a valid user (listed in field 7 of oraback.conf).&nbsp; If the user
id running the backup is not a valid user, the script will not continue.&nbsp;</font></li>

<li>
<font face="Arial,Helvetica">If it is a valid user, oraback.sh then looks
to see whether the word skip is in field 2.&nbsp; If so, it skips the backup
once, and removes the word skip from oraback.conf.&nbsp; (This allows a
DBA to manually skip tonight's backup, but does not allow the DBA to accidentally
disable backups forever.)</font></li>
</ul>
<font face="Arial,Helvetica">The script then does one of the following,
depending on which arguments (if any) it receives:</font>
<br>&nbsp;
<ul>
<li>
<font face="Arial,Helvetica">It backs up everything</font></li>
</ul>
<font face="Arial,Helvetica">If given no arguments, it performs a backup
of all instances listed in Oracle's oratab file.</font>
<br><font face="Arial,Helvetica">$ oraback.sh&nbsp;</font>
<br>&nbsp;
<ul>
<li>
<font face="Arial,Helvetica">It backs up selected instances</font></li>
</ul>
<font face="Arial,Helvetica">If given one or more instance names (ORACLE_SIDs,
or SIDs for short) as arguments, the script performs a backup of each of
them.</font>
<br><font face="Arial,Helvetica">$ oraback.sh ORACLE_SID1 ORACLE_SIDn&nbsp;</font>
<ul>
<li>
<font face="Arial,Helvetica">It schedules a backup for later</font></li>
</ul>
<font face="Arial,Helvetica">If called with at as an argument (this is
what would be in cron), the script checks oraback.conf to see whether the
day in field 3 (the cold backup day field) is today.&nbsp; If so, it sets
the variable $TIME to the time in field 4.&nbsp; If not, it sets $TIME
to the time in field 5. The script then schedules an at job that will run
oraback.sh at the time specified by $TIME.</font><font face="Arial,Helvetica"></font>
<p><font face="Arial,Helvetica">$ oraback.sh at&nbsp;</font>
<br><font face="Arial,Helvetica"></font>&nbsp;
<h2>
<font face="Arial,Helvetica">Deciding where and how to back up</font></h2>
<font face="Arial,Helvetica">Oraback.sh then checks the hostname.master
line in oraback.conf to find out if: (a) there is a tape device in field
6.&nbsp; If so, it labels the tape, making sure the no-rewind device is
being used; and (b) there is a number in field 8.&nbsp; If so, it will
perform that many simultaneous copies of database files.</font><font face="Arial,Helvetica"></font>
<p><font face="Arial,Helvetica">Next, oraback.sh asks Oracle questions
that will determine how (or if) the SID will be backed up.&nbsp; It asks
if</font>
<ul>
<li>
<font face="Arial,Helvetica">The instance is online.&nbsp; If so, oraback.sh
makes a set of configuration files needed later</font></li>

<li>
<font face="Arial,Helvetica">Archiving is running</font></li>

<li>
<font face="Arial,Helvetica">The instance is excluded from hot backup</font></li>

<li>
<font face="Arial,Helvetica">This is a cold backup.&nbsp; If so, it shuts
down the instance.</font></li>
</ul>
<font face="Arial,Helvetica">The script assumes that all instances want
hot backups (though you may specify cold backups), which requires automatic
archiving of redo logs.&nbsp; Oraback.sh warns if any instances do not
have automatic archiving turned on.&nbsp; It continues to complain until
this situation is corrected or oraback.conf is customized for that instance.&nbsp;
(You do this by editing oraback.conf.)</font>
<h3>
<font face="Arial,Helvetica">If it抯 a hot backup</font></h3>
<font face="Arial,Helvetica">If the instance is online, logs are on, and
the instance is not excluded from hot backups, then the script:</font>
<ol>
<li>
<font face="Arial,Helvetica">Puts each tablespace into backup mode by using
the svrmgrl command begin backup.&nbsp;</font></li>

<li>
<font face="Arial,Helvetica">Copies that tablespace's files to the backup
device</font></li>

<li>
<font face="Arial,Helvetica">Takes the tablespace out of backup mode with
the svrmgrl command end backup&nbsp;</font></li>
</ol>
<font face="Arial,Helvetica">These three steps are the core of the hot
backup.&nbsp; While the tablespace is in backup mode, the files can be
safely backed up.</font><font face="Arial,Helvetica"></font>
<p><font face="Arial,Helvetica">The script supports simultaneous copying
of individual data files to dramatically increase the speed of the backup.&nbsp;
Depending on how many files there are per tablespace, there may be one
or more tablespaces in backup mode at once.&nbsp; This is done in order
to perform the number of concurrent file copies (using dd) that are specified
in field 8 of oraback.conf, if you are using this feature.</font>
<h3>
<font face="Arial,Helvetica">After all data files are backed up</font></h3>
<font face="Arial,Helvetica">Next, the script forces a checkpoint and archive
log switch, which causes the online redo log to be sent to an archived
redo log.&nbsp; It should be noted that it forces a log switch using the
command alter sytem archive log current, instead of the older alter system
switch logfile.&nbsp; The reason for this is that switching log files does
just that, switches the log file and immediately returns the svrmgr prompt.&nbsp;
The archive log current command waits until the copy of the old redo log
to its archived location is done before it returns the prompt.&nbsp; This
is because the next thing the script is going to do is to copy this archived
redo log to the backup location for safekeeping.&nbsp; If we used the old
command, we might by copying it from the archived log location while it
is being created.&nbsp; That way we are assured that the file we are copying
is stable.</font><font face="Arial,Helvetica"></font>
<p><font face="Arial,Helvetica">The script then backs up the control files
to disk using both svrmgr and a manual copy.&nbsp; The manual copy is just
for the paranoid; it's not a supported method of backing up the control
file .&nbsp; Finally, the script makes copies of the essential redo logs
and compresses them.&nbsp; (Essential logs are those that span the time
of the backup.)&nbsp; If the backup device is a tape, it then backs up
all files that were sent to disk to the tape device.</font>
<h3>
<font face="Arial,Helvetica">If it抯 a cold backup</font></h3>
<font face="Arial,Helvetica">If the instance is offline, oraback.sh only
needs to copy the data files to the backup device.&nbsp; The script then
backs up the control files and redo logs the same way it does during a
hot backup.&nbsp; This is perhaps the only time that manually copying the
control files and online redo logs does any good.&nbsp; That's because
one could use these files to do a restore of the database to this point,
without it ever knowing what happened.&nbsp; To do that, all the control
files and online redo logs would be needed.</font>
<h3>
<font face="Arial,Helvetica">Special cases</font></h3>
<font face="Arial,Helvetica">If the instance is online, but archiving is
off, oraback.sh checks oraback.conf for a line that reads:</font><font face="Arial,Helvetica"></font>
<p><font face="Arial,Helvetica">HOST:ORACLE_SID:NOARCHIVELOG:[offline|nohotbackups]</font><font face="Arial,Helvetica"></font>
<p><font face="Arial,Helvetica">If that line is not found, oraback.sh complains
and sends you mail.&nbsp; That is because archiving must be on in order
to do hot backups.&nbsp; If the line is found, it looks for the word offline
on that same line.&nbsp; This tells oraback.sh that this instance is not
supposed to have archive logs running, and it should always do an offline,
or cold, backup of this instance.&nbsp; If it sees the word offline, oraback.sh
shuts down the instance, performs a cold backup, and then restarts the
instance.&nbsp; (This is one of the ways to customize oraback.sh for different
instances.)</font><font face="Arial,Helvetica"></font>
<p><font face="Arial,Helvetica">If the instance is online, oraback.sh also
looks for a line in oraback.conf that reads:</font><font face="Arial,Helvetica"></font>
<p><font face="Arial,Helvetica">HOST:ORACLE_SID:::nohotbackup</font><font face="Arial,Helvetica"></font>
<p><font face="Arial,Helvetica">This tells oraback.sh that although ORACLE_SID
qualifies for a hot backup (it has archiving on), oraback.sh should not
do hot backups of this instance.&nbsp; This is best suited for a development
database, where the weekly cold backup is sufficient.&nbsp; If this line
is found, the script skips this instance when performing a hot backup.</font>
<h3>
<font face="Arial,Helvetica">Customizing backups of an instance</font></h3>
<font face="Arial,Helvetica">If there is an instance that will not run
archiving or hot backups, put a line in oraback.conf that starts with:</font>
<br><font face="Arial,Helvetica">hostname:ORACLE_SID::::</font>
<ol>
<li>
<font face="Arial,Helvetica">Put NOARCHIVELOG in field 3 if the instance
does not use archiving.</font></li>

<li>
<font face="Arial,Helvetica">Put offline in field 4 if the instance does
not use archiving, and oraback.sh should do a cold backup done every time.</font></li>

<li>
<font face="Arial,Helvetica">Put nohotbackups in field 5 to skip hot backups
for this instance.&nbsp; (It will only be backed up when cold backups run).</font></li>
</ol>

<h3>
<font face="Arial,Helvetica">Testing Oraback.sh</font></h3>
<font face="Arial,Helvetica">For testing, select a small instance and run
the following command as Oracle:</font><font face="Arial,Helvetica"></font>
<p><font face="Arial,Helvetica">$ /usr/local/bin/oraback.sh &lt;instance></font><font face="Arial,Helvetica"></font>
<p><font face="Arial,Helvetica">Be aware that if the word offline is in
oraback.conf, or if the day that is specified for cold backups is today,
the instance will be shut down!</font>
<br><font face="Arial,Helvetica">If this test functions properly, put an
entry in Oracle's cron or in the at system.&nbsp; Add a cron entry that
contains the command /usr/local/bin/oraback.sh at, schedule to run at around
12:00.&nbsp; It checks the oraback.conf and schedules an at job that will
perform the backup.</font>
<h3>
<font face="Arial,Helvetica">Using Oraback.sh</font></h3>
<font face="Arial,Helvetica">The best way to use this program is to have
one single oraback.conf file that is NFS-mounted or shared to all Oracle
systems.&nbsp; That way, all cron or at entries can run at 15:00, and backup
configuration changes (system-wide or otherwise) can be made by editing
one file.&nbsp; For example, to cause all Oracle backups to be skipped
tonight, instead of having to edit a number of cron or at entries, edit
this one file before 15:00.&nbsp; That way, it will see the word skip in
there and not run backups that evening.&nbsp; (It will, however, take this
word out so backups will run tomorrow night.)</font><font face="Arial,Helvetica"></font>
<p><font face="Arial,Helvetica">Set the SUCCESSMAIL flag to Y, to be mailed
every time oraback.sh backup runs, successful or otherwise.&nbsp; That
allows a quick email check in the morning to see that all backups ran successful.&nbsp;
Simply check the subject line, since it will say ERROR if oraback.sh had
any kind of errors.</font>&nbsp;</td>
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