Thanks for all the answers. So SSDs (Looking at  SSD caching) for the database 
storage and 10GB  per TB of total backup data on the safer side. 

--------------------------------------------
On Thu, 6/12/14, Erwann Simon <erwann.simon AT FREE DOT FR> wrote:

 Subject: Re: [ADSM-L] TSM and VTL Deduplication
 To: ADSM-L AT VM.MARIST DOT EDU
 Date: Thursday, June 12, 2014, 8:47 AM
 
 Hi,
 
 I'd rather say 6 to 10 times, or 10 GB of
 DB for each 1 TB of data (native, not deduped) stored.
 
 -- 
 Best
 regards / Cordialement / مع تحياتي
 Erwann SIMON
 
 -----
 Mail original -----
 De: "Norman
 Gee" <Norman.Gee AT LC.CA DOT GOV>
 À: ADSM-L AT VM.MARIST DOT EDU
 Envoyé: Jeudi 12 Juin 2014 16:55:29
 Objet: Re: [ADSM-L] TSM and VTL
 Deduplication
 
 Be prepare
 for your database size to double or triple if you are using
 TSM deduplication.
 
 -----Original Message-----
 From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU]
 On Behalf Of Prather, Wanda
 Sent: Thursday,
 June 12, 2014 7:15 AM
 To: ADSM-L AT VM.MARIST DOT EDU
 Subject: Re: TSM and VTL Deduplication
 
 And if you are on the
 licensing-by-TB model, when it gets un-deduped (reduped,
 rehydrated, whatever), your costs go up!
 
 -----Original Message-----
 From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU]
 On Behalf Of Dan Haufer
 Sent: Thursday, June
 12, 2014 9:48 AM
 To: ADSM-L AT VM.MARIST DOT EDU
 Subject: Re: [ADSM-L] TSM and VTL
 Deduplication
 
 Understood.
 Thanks !
 
 --------------------------------------------
 On Thu, 6/12/14, Ehresman,David E. <deehre01 AT LOUISVILLE DOT EDU>
 wrote:
 
  Subject: Re:
 [ADSM-L] TSM and VTL Deduplication
  To: ADSM-L AT VM.MARIST DOT EDU
  Date: Thursday, June 12, 2014, 5:33 AM
 
  If TSM moves data from a
  (disk) dedup pool to tape, TSM has to un-dedup
 the data as  it reads it