10
Aug
06

Check your user passwords

A good tool to monitor your users password is the one developed by Red database security.

It’s called checkpwd.

Download it on there website
On the command line simply type:

C:\checkpwd [oradba_user]/[password]@[tns entry] [your_password _file _location.txt]
On oracle 8i it’s easy but now with Oracle 10g, to connect as sysdba we have to specify for example in SQLPLUS:

SQL>conn sys/[password] as sysdba

This is apparently not taken into account yet and it fails to recognize the command with the extra words “as sysdba”.

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08
Aug
06

The recovery manager – RMAN

Here is one tool that DBA’s will be happy to use.

On oracle 9i it was still having some problem, on Oracle 10.2 it’s working just fine.

Using RMAN, it’s now possible to create some backups strategy with simplicity.

Let’s take the most simple example:

RMAN> backup database; Frankly, if you didn’t know that you might think it’s too easy to be true.

RMAN>backup archivelog all;

Personally I would have allowed RMAN to understand backup all archive log which is more human.

Oops! I’ve just lost a tablespace Oo’

RMAN>restore tablespace SYSTEM01;

Oops! I’m not too sure what’s wrong finally

RMAN>restore database;

RMAN>recover database;

The Recovery Manager also features a direct tape channel provided you can configure it with your provider driver. It’s a bit tricky.

It will check a retention time what you would have set up. I use 15 days.

However, you must make sure you have enough disk space to allow 15 backups living together on the same disk.

That was just a introduction to RMAN. I will come back we advanced commands later when I have a little time.

I will also show how RMAN looks like in the OEM and how it is possible to give the task to someone less knowledgeable in Oracle thanks to the cool graphical interface.

I mean, it does the backups but it still need to be checked on.

25
Jul
06

How to shutdown oracle if the server is too slow on windows

If for some reasons a server is very slow and the shutdown immediate command can be expected to take ages…

Go for the kill of the Oracle Service in control panel>configuration>services

Find OracleService[OracleSID] and stop it.

Shutting down Oracle by stopping the Oracle service makes a clean stop of the database as opposed to shutdown abort which must be avoided at all costs.

Shutting down with an abort can create fuzzy files which is all DBA’s nightmare.

24
Jul
06

Installing Oracle using what RAID system?

I realise it is vastly unknown what RAID system must be used to work with Oracle.

Actually the answer is: It depends.

But to answer it there’s just a simple question to ask:

Will my Oracle database write a lot on the disks or read a lot?

How to know?

1) The use of the database (Is it datawarehouse (READ) or some invoice keying (WRITE)?).

2) The frequency of backups.

3) Consider the amount of users.

If it is something involving a lot of keying then it’s best to use a RAID1 or RAID1+0. Some simple mirroring would greatly improve the performance of the server.

If it is a datawarehouse type application where the data are pushed on the server once everyday and then it’s only SELECT statements all day long then RAID5 might do. But the process to push your data in the datawarehouse might take little longer as a consequence.

If you are considering RAID5 anyway, think about this:

1) Use a minimum of 5 disks on your server

2) Enable your writing cache (make sure it’s battery backed cache)

In the case you already use RAID5 with some keying applications, and there’s only a few users, then don’t forget your backups, your tape device. All these are very ressource consuming. At those times where you do backups, the users might feel the server very slow.

To summarize:

Not Datawarehouse> Use RAID1 or RAID1+0 Datawarehouse> Use RAID5 with a very minimum of 5 disks.

19
Jul
06

Changing sysman and dbsnmp passwords – It ain’t that easy

And of course it’s not that easy!

Actually this is quite annoying.

I have 2 concerns: Having my backups working properly as well as the DB Console.

But also renew my passwords from time to time.

And here we are sys and system’s passwords are luckily easy to change.

But what about sysman and dbsnmp?

Those are not. Try to change it and you will have your backups stop working, OEM throws in tons of errors and soon you will be asking yourself why the hell you wanted to change those passwords in the first place.

The reason

Sysman user is the schema of the standalone repository of the 10g EM DB Control.

If you have change only dbsnmp password your backups will work and the DB console as well but all the cool graphics that I like to show to our customers will disappear and that’s not cool.
There are 2 procedures. 1 for each passwords

Changing sysman password

So, since it’s the schema of the standalone repository, the DB console must be shut down.

C:\emctl stop dbconsole

This should stop dbconsole and the agent.

Have a check first.

C:\emctl status dbconsole

C:\emctl status agent

On windows the agent is very often not shutdown properly… So do it using the services screen find your Oracle10Agent service and make sure it’s not started.

When this is done, open an sqlplus console and throw in the command to change password

C:\set oracle_sid= [your SID]

C:\sqlplus / as sysdba

SQL>alter user sysman identified by [New Password];

Then check the new password by connecting with sysman user. This is to make sure sysman is not locked. Because when the password is changed and you try to reach the OEM, it will locked the sysman user.

SQL>conn sysman/newpassword

connected.

Ah that’s cool

if you get

ora-28000: account is locked

Then unlock it first.

SQL> alter user sysman account unlock;

Now that you get your new password and you are sure the account is not locked, you have to modify the emoms.properties file.

It’s located at ORACLE_HOME\[HOST]_[SID]\sysman\config. Replace HOST with your computer name and SID with your SID.

There are 2 parameters to modify:

oracle.sysman.eml.mntr.emdRepPwd= [Your encrypted password]

oracle.sysman.eml.mntr.emdRepPwdEncrypted=True

Change [Your encrypted password] with your new password in the first parameter

and change True to False in the second parameter.

Wait a minute. That is not very safe! The password is not encrypted!

That’s where Oracle 10g is cool. It’s not like you have a choice here.

As soon as you restart Dbconsole and Oracle agent, it will change false to true and your password will look like a bunch of numbers and letters again (Geeks love that) 🙂

So just type in:

C:\emctl start dbconsole

C:\emctl start agent

Again, if the agent is not started, try to do it through the service window. I found it to work much better than the command line for Oracle Agent.

Changing dbsnmp password

It’s about the same thing except it’s another configuration file.

Stop Db Console and Oracle agent. Just like before.

Make sure it’s stopped just like before.

Modify your user password just like before except use alter dbsnmp instead of sysman.

Finally make sure it’s not locked.

We have to modify the file targets.xml this time and that one is located at:

ORACLE_HOME\[HOST]_[SID]\sysman\emd

Look for this line:

<Property NAME=”password” VALUE=”<[Your encrypted password]>” ENCRYPTED=”TRUE”/>

Just like before, change [Your encrypted password] to your new password and change TRUE to FALSE.

Just like before, restart your DB Console service and Oracle Agent service.

Make sure they are working.

C:\emctl status dbconsole

C:\emctl status agent

Voila! It’s all done.

The bottom line is: When you want to change a password that doesn’t look like a collegue name, find some documentation on it first. A good way is to google: Problem [user].

You’ll find a lot of them!




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