SnapManager SQL : Point in Time Restore after the last SnapShot

[Mathias_Robichon]

Hi Folk,

Can I restore a DB with SMSQL after the last SMSQL backup by using the last current logs ?

I know that is possible to restore with PTR (point-in-time recovery) in a point between 2 SnapShots (S and S-1 for instance), but I'm not sure that is possible to do that after the last one.

I

f not, anybody could give me a method to do a hand log replay ?

Thanks a lot for your help.

Mathias

[welch]

Mathias,

Yes, you can do either an up to the minute restore, or a point in time restore using SnapManager for SQL.  As long as you have the .trb (.trn) files available, while walking through a restore using SMSQL, you will get an option to leave the database operational, bring it online in read-only, or bring it into stand-by mode available for log replay.  The third option will allow you to create an undo file and restore the database manually playing the t-logs one by one as you would with a traditional sql restore.  As long as you have the logs available, you should be able to replay them. 

Keep in mind, however, that SMSQL can automatically replay these logs for you should you need to do a restore.  Typically, SMSQL will attempt to restore the database using the last full snapshot backup taken.  Then, assuming you are using SMSQL to schedule your t-log dumps, it will replay any logs available in the SnapInfo directory as far forward as possible.  This is considered an "Up to the minute" restore.

[ple]

Hello Welch,

Thks for your answer.

What is the frequency that we can perform the backup of only the transaction logs ? 5 min is it possible , acceptable ?

Best regards

Philippe

[welch]

You should be able to backup transaction logs as frequent as required.  Every 5 minutes is aggressive, but acceptable as long as your server and storage hardware can support it.  Remember there is overhead in SQL every time you dump a transaction log as well as overhead associated with taking a snapshot of the log volume.  If you set the backups to run every 5 minutes and encounter odd performance issues, then it is likely you will need to do them less frequent.  I have many customers that successfully do transaction log dumps every 15 minutes.  In the end it all depends on your environment.