Wanda, when id dup finds duplicate chunks in the same storagepool, it will raise the pct_reclaim value for the volume it is working on. If the pct_reclaim isn't going up, that means there are no duplicate chunks being found. Id dup is still chunking the backups up (watch you database grow!) but all the chunks are unique.
Is it possible that the ndmp agent in the storage appliance is putting in unique metadata with each file? This would make every backup appear to be unique in chunk-speak. I remember from the v6 beta that the standard v6 clients were enhanced so that the metadata could be better identified by id dup and skipped over so that it could just work on the files and get better dedup ratios. If id dup doesn't know how to skip over the metadata in an ndmp stream, and the metadata is always changed, then you will get very low dedup ratios. If you do a 'q pr' while the id dup is running, do the processes say they are finding duplicates? Bill Colwell Draper Lab -----Original Message----- From: ADSM: Dist Stor Manager [mailto:[email protected]] On Behalf Of Prather, Wanda Sent: Monday, November 21, 2011 11:41 PM To: [email protected] Subject: Stupid question about TSM server-side dedup Have a customer would like to go all disk backups using TSM dedup. This would be a benefit to them in several respects, not the least in having the ability to replicate to another TSM server using the features in 6.3. The customer has a requirement to keep their NDMP dumps 6 months. (I know that's not desirable, but the backup group has no choice in the matter right now, it's imposed by a higher level of management.) The NDMP dumps come via TCP/IP into a regular TSM sequential filepool. They should dedup like crazy, but client-side dedup is not an option (as there is no client). So here's the question. NDMP backups come into the filepool and identify duplicates is running. But because of those long retention times, all the volumes in the filepool are FULL, but 0% reclaimable, and they will continue to be that way for 6 months, as no dumps will expire until then. Since the dedup occurs as part of reclaim, and the volumes won't reclaim -how do we "prime the pump" and get this data to dedup? Should we do a few MOVE DATAs to get the volumes partially empty? Wanda Prather | Senior Technical Specialist | [email protected]<mailto:[email protected]> | www.icf.com<http://www.icf.com> ICF International | 401 E. Pratt St, Suite 2214, Baltimore, MD 21202 | 410.539.1135 (o) Connect with us on social media<http://www.icfi.com/social>
