Reuse delay and TSM DB Backup Retention ..why related????

[sasa]

Hi ,

I have a question regarding reletionship between Reuse delay parameter of storage pools and time period for which TSM DB backups are retained.



According to IBM TSM manuals , it is always recommended to have reuse delay on copy storage pools only and the value of this should be greater than number of days for which TSM database backups are retained .



For example , if my company takes TSM database backups every weekend , and retain it for four weeks , then it means i am retaining these backups for nearly 28 days and so reuse delay should be set up to 29 or 30 etc.... is this thing correct or my concept is wrong ???





why this relationship exist as a recommendation !!! retaining data cartridges with already expired data on it with state of pending , have no sense as per my understanding



I will appreciate if someone make clarification onto it





thanks



SASA,

 

[kweigel]

Hi sasa,

think about the need to restore the database. It contains pointers, which dateset is on which tape. If ou have overwritten your tapes in the meantime, you'll never find your data. So, as long as you keep your database backups, you shouldn't overwrite your Copypool-tapes. But, by the way, is a retention od 28 days useful for you ? In case of a DB-restore you loose all backups of a whole month.

Regards,

karl

 

[sasa]

hi,

thanks for answering me .



Infact , for disaster recovery , company policy is to depend upon weekly backup cartridges

which are taken out of library along with TSM DB backups.



In case of "real need " therefore , we restore only latest weekly backup and dont go for latest backup ( previous night let's say).



Now returning to my question once again !! I have already set my data retention policy for these weekly pools as such to expire data on these cartridges after four weeks . Now when data is expired , then due to addition of resuse delay of 29 or 30 days , this expired data is kept for 29 or 30 days more .... ( in pending state ).



is this correct thing to do or needs some modification in same context.



thanks for help

 

[sai]

Hello Guys,

Can i know where is this reuse delay option?? and how can i set it

I have like 50 tapes that became scratches and are not being used they were DB tapes. Need help on this.

Thanks,

Sai

 

[anilkumar451]

Hi Sai,

Reusedelay is in define stgpool or update stgpool commands. it is only used for copy pools not for primary pools. reuse delay should always greater than or equal drmdbbackupexpiredays. Hope it helps.

 

[moon-buddy]

hi,

thanks for answering me .

Infact , for disaster recovery , company policy is to depend upon weekly backup cartridges

which are taken out of library along with TSM DB backups.

In case of "real need " therefore , we restore only latest weekly backup and dont go for latest backup ( previous night let's say).

Now returning to my question once again !! I have already set my data retention policy for these weekly pools as such to expire data on these cartridges after four weeks . Now when data is expired , then due to addition of resuse delay of 29 or 30 days , this expired data is kept for 29 or 30 days more .... ( in pending state ).

is this correct thing to do or needs some modification in same context.

thanks for help

I have a bigger issue with the setup of your system.

Weekly backups of the database would not cut it. If you have a disaster, you can only recover from the previous week. What happens to the data backed up daily? All is lost which means the company will either go out of business since it cannot collect money owed to it because AR (Accounts Receivable) data was lost, etc.

If you do this, might as well backup once a week.

The prudent way is to backup the DB daily.

Here is what I think must be the backup setup:

1) Backup DB daily
2) Keep backups for 8 days
3) Set reuse delay to 10 days
4) (optional) Set data retention to legal requirements