As per Information Center:
"If this option is specified when restoring from an online backup
image, error SQL2537N will be returned."
So you you are left with rolling forward. That being said, you could try the following
db2 rollforward db mydb to end of backup and complete
According to the information for rollforward command
END OF BACKUP
Specifies that all partitions in the partitioned database should be rolled forward to the minimum recovery time. See Examples section
below for an example.
This should restore whatever it is you are attempting to restore up to the point of the end of the backup and not include any rolling forward through transactions logs that may be occurring after the backup. Normally you still have to issue at least this statement for a restore from an offline backup where you use archived logs.
I personally haven't tried nor had the need to do an online and only rollforward to the end of the backup. Give it a shot and let us all know what happens.
EDIT: To answer your questions below: You must have archival logging
enabled in order to take online backups. You can still take offline
backups with archival logging. You do not have to switch back to
circular to do so. However, once you have archival logging enabled,
regardless of whether you are restoring from an offline or an online
backup, you must perform a rollforward when you are done. No way
around it. See my own previous question on this.
In order to set up archival logging, you will need to alter the
database configuration parameter LOGARCHMETH1. By default, this is
set to OFF, which means circular logging. Your choices for it are as
follows:
DISKTSMUSEREXITVENDORLOGRETAIN
LOGRETAIN tells DB2 to leave the archived logs in the logging
directory. It will not clean up any of these logs for you (leaving you
as the DBA to do so). USEREXIT leaves it up to a non-IBM third party
tool to take care of storing and archiving your logs (usually hand coded in C). Not too
many people use this anymore from what I understand. DISK and TSM seem
to be used a fair amount. DISK tells DB2 where you want to archive
your logs off to (although with a few other parameters set, DB2 can
automatically clean up logs no longer needed-I'll show you that
below). TSM tells DB2 to let IBM's Tivoli Storage Manager to archive
off the logs. There are a few other settings you have to get into for
that to work. Where I work, we haven't tried that yet.
And lastly, VENDOR is used to use a third-party vendor product to archive off your logs.
To set up archival logging of to a different disk spot and have DB2
automatically clean things for you, you can do the following
(NOTE:these are in Unix path)
db2 connect to mydb user <admin user> using <admin user password>
#NOTE THE double and single quotes needed on the command line in Unix
db2 "update db cfg using logarchmeth1 'DISK:/dbarch/dblogs'"
db2 update db cfg using num_db_backups 2
db2 update db cfg using rec_his_retentn 2
db2 update db cfg using auto_del_rec_obj on
db2 terminate
This will tell DB2 to keep 2 full backups for at least two full days.
Two backups have been kept for two days and another one is taken, the
oldest backup will be deleted by DB2. DB2 will also then clean up any
logs that were between the now deleted backup and the next oldest
retained backup.
Also note: once you switch to archival logging, DB2 will require you
to immediately take an offline backup as your next action (ie, the
database will be placed into BACKUP PENDING mode) and you will be
unable to do anything else until you do so.
Hope this helps!
Unfortunately, it's not possible to take an online backup of a DB2 database if it's in circular logging mode, which is the default for DB2 databases when they are created.
You can check whether your database is using circular logging by issuing:
./db2 get db cfg for dbemp | grep LOGARCH
If both LOGARCHMETH options are switched off...
First log archive method (LOGARCHMETH1) = OFF
Second log archive method (LOGARCHMETH2) = OFF
... then you'll need to change your database configuration to use archive logging before backups can be taken. I'm not 100% sure of this but I believe you'll need to restart your database and take an offline backup before you can start taking online backups.
There's an overview of how to do this in IBM's "configuring database logging options" documentation.
Note that if you change from CIRCULAR LOGGING to ARCHIVE LOGGING, you'll need to figure out what to do with your archived log files. Storing them on SAN/NAS/Tape to allow roll-forward recovery can be a really good idea if this data is important to you.
Best Answer
[This answer was also posted to the duplicate question on Stack Overflow]
When you perform an online restore, DB2 must lock the tablespace(s) you are trying to restore. The restore process essentially overwrites the file on disk containing the tablespaces' data. This is incompatible with applications using data in the same tablespace while the restore occurs.
If your database has all data in a single tablespace, then an online restore is not particularly useful. If you have multiple tablespaces in the database, applications may be able to continue functioning while the corrupted tablespace(s) are restored, but of course this requires some planning in your application and database design.