Data Domain: How does Veeam UI report Capacity Space for DDBOOST Storage Unit

When Hard Limit Quota is enabled on a Data Domain LSU/Mtree, Veeam UI may display varying capacity values across different DDR system. This behavior depends on how Data Domain calculates physical capacity and how Veeam processes these values.

Note: When Hard Limit and Soft Limit Quota are both set, Hard Limit Quota gets precedence over Soft Limit Quota. 

Calculation Methodology

Case 1: Quota is Enabled, Hard Quota Limit is Set and when 'logical used' and 'physical used' on DD!= 0 (Is Not Zero)

Data Domain estimates approximate physical capacity and physical free space using the deduplication ratio, also known as the total‑comp factor X.

Sub Case 1: Deduplication > 1:

• Approx. physical space
  = MIN(quota_hard_limit, (precomp size of the mtree/Storage-Unit + physical available space in DDR * X)) / X

• Approx. free space
  = Approx. physical available space in DDR - (precomp size of the mtree/X)

Corner Case (Deduplication > 1): If Precomp Size of Storage-Unit > Quota Limit:

• Capacity = Total Physical space on DDR

• Free space = Total Physical free space available on DDR

Sub Case 2: Deduplication < 1:

• Approx. physical space
  = MIN(quota_hard_limit, total physical space on DDR)

• Approx. free space
  = MIN((quota_hard_limit - precomp size of Mtree/Storage-Unit), physical available space in DDR)

Corner Case (Deduplication < 1): If Precomp Size of Storage-Unit > Quota Limit:

• Capacity = quota_hard_limit

• Free Space = 0

Case 2: Quota is Enabled, Hard Quota Limit is Set but when 'logical used' OR 'physical used' on DD = 0 (Is Zero)

• Capacity
  = MIN(quota_hard_limit, total physical space on DDR)

• Free Space
  = MIN(quota_hard_limit, total physical free space available on DDR)

Case 3: Hard Quota Limit is Not Set, or Quota is Not Enabled. 

Defaults to standard behavior, where the physical stats of the whole DDR are returned. 

• Capacity = Total Physical space on DDR

• Free space = Total Physical free space available on DDR

   

"Approx. physical space": Boost Calculated Value passed to consumer of Dell EMC Data Domain Boost Application Programming Interface (API) for computing Capacity Space
"Approx. free space": Boost Calculated Value passed to consumer of Dell EMC Data Domain Boost API for computing Free Space
"Deduplication Ratio (X)": Deduplication ratio or Total Comp Factor of Data Domain file system (DDFS) Active tier 
"quota_limit": It is the Quota Limit set for mtree/Storage Unit and if a hard-limit is present then it gets precedence over soft-limit
"precomp size of mtree": Total Pre-Comp for the respective mtree/Storage Unit
"physical available space in DDR": Postcomp Available Space on the DD.

How Veeam Processes Boost-Calculated Values:

Quota Enabled Check:

• Veeam considers the quota 'enabled' if the Boost-reported capacity is between [0, /data: post-comp Size GiB] (from DDFS CLI).
  If Enabled:
  Capacity (UI) = Boost Value * Total Comp Factor (X) 
  If Disabled:
  Capacity = /data: post-comp Size GiB. 

Describing this behavior on Veeam with an Example: 

Example 1: DD1 with Veeam1
From the screenshot below, can see "Capacity" displayed on Veeam shows 63.5 TB, & "Free space" shows as 15.6 TB.
 

Mtree List
----------
Name                            Pre-Comp (GiB)   Status   
--------------------------      --------------   ------
/data/col1/veeambkup               662358.2        RW 
Quota Show All
--------------
Mtree                           Pre-Comp (MiB)   Soft-Limit (MiB)   Hard-Limit (MiB)
-----------------------------   --------------   ----------------   ----------------
/data/col1/veeambkup               376082346        10737418240        11811160064

Active Tier:
Resource           Size GiB   Used GiB   Avail GiB   Use%   Cleanable GiB*
----------------   --------   --------   ---------   ----   --------------
/data: pre-comp           -   662358.2           -      -                -
/data: post-comp    65016.5    48929.3     16087.1    75%            166.5
/ddvar                 78.6       22.8        51.9    30%                -
/ddvar/core           251.9      119.8       119.2    50%                -
----------------   --------   --------   ---------   ----   --------------
 * Estimated based on last cleaning of 2024/10/23 23:17:46.

                   Pre-Comp   Post-Comp   Global-Comp   Local-Comp      Total-Comp
                      (GiB)       (GiB)        Factor       Factor          Factor
                                                                     (Reduction %)
----------------   --------   ---------   -----------   ----------   -------------
Currently Used:*   662358.2     48929.3             -            -    13.5x (92.6)

As deduplication (13.5) is greater than 1:

 Approx. physical space:
= MIN(quota_hard_limit, (precomp size of the mtree + physical available space in DDR * X)) / X

Parameters:

Hard-limit quota = 11811160064 MiB which in Terabytes = 12384.89 TB
Precomp size = 662358.2 GiB which in Terabytes = 711.2 Terabytes (TB).
DD physical available space = 17.2 Terabytes (TB) 
Overall deduplication factor (X) = 13.5x

Calculations:

Approx. physical space = MIN(12,384.89 TB, (711.2 TB + 17.2 TB * 13.5)) / 13.5 
                       = MIN(12,384.89 TB, 943.4 TB)/ 13.5 
                       = 943.4 TB / 13.5  = 69.88 TB (~ 63.5 TiB)

Capacity shown on Veeam1 = 63.5 TiB [It is NOT multiplied with "X"(Deduplication) since it exceeds postcomp size] 

Approx. Free Space = 65080.8 GiB - (662358.2 GiB / 13.5)
                   = 65080.8 GiB - 49063.5 GiB
                   = 16017.3 GiB

Free Space shown on Veeam1 = 15.6 TiB (~ 15.6 TiB) [GiB to TiB conversion]

Example 2: DD2 with Veeam2
From the screenshot below, we can see "Capacity Space" displayed on Veeam shows 121.9 TB & "Free Space" shows as 23.1 TB. 


 

Mtree List
----------
Name                         Pre-Comp (GiB)   Status
--------------------------   --------------   ---------
/data/col1/veeambckp               101171.1   RW/Q/RLCE

Quota Show All
--------------
Mtree                        Pre-Comp (MiB)   Soft-Limit (MiB)   Hard-Limit (MiB)
--------------------------   --------------   ----------------   ----------------
/data/col1/veeambckp              103599239        10737418240        11811160064

Active Tier:
Resource           Size GiB   Used GiB   Avail GiB   Use%   Cleanable GiB*
----------------   --------   --------   ---------   ----   --------------
/data: pre-comp           -   114922.6           -      -                -
/data: post-comp    13276.2    10910.9      2365.3    82%            816.0
/ddvar                 47.1       18.2        26.5    41%                -
/ddvar/core           108.1        5.4        97.2     5%                -
----------------   --------   --------   ---------   ----   --------------
 * Estimated based on last cleaning of 2024/11/20 20:57:38.

                   Pre-Comp   Post-Comp   Global-Comp   Local-Comp      Total-Comp
                      (GiB)       (GiB)        Factor       Factor          Factor
                                                                     (Reduction %)
----------------   --------   ---------   -----------   ----------   -------------
Currently Used:*   114922.6     10910.9             -            -    10.5x (90.5)

As deduplication (10.5) is greater than 1:
 

Approx. physical space:
= MIN(quota_hard_limit, (precomp size of the mtree + physical available space in DDR * X)) / X

Parameters:

Hard-limit quota = 11811160064 MiB which is 11534336 GiB
Precomp size = 101171.1 GiB
DD physical available space = 2365.3 GiB
Overall deduplication factor (X) = 10.5x

Calculations:

 Approx. physical space =(Min(11534336 GiB, (101171.1 GiB + 2365.3 TB * 10.5)))/ 10.5 
                       =(Min(11534336 GiB, 126006.7))/ 10.5
                       = 126006.7 GiB / 10.5
                       = 12000.64 GiB  

Approx. physical space = 12000.64 GiB [which is 11.71 TiB]

But 11.71 TB do not show on the Veeam UI, rather the Veeam UI shows 121.9 TB which is approx. 122 TB. And so this is the difference compared to Example 1.

In this case, the "Boost-Calculated Value(Approx. physical space) = 12000.64 GiB " is less than "Post-Comp Size GiB" since "/data: postcomp" is 13276.2 GiB. 
Thereby Veeam multiplies the obtained "Approx. physical space" with "Total Comp Factor (Deduplication)" and shows the result as Capacity space in UI.
 

Capacity shown on Veeam2 = Boost Calculated Value(Approx. physical space) * Total Comp Factor (Deduplication) 
                         = 11.71 TiB * 10.5x = 122.9 TiB  

Capacity shown on Veeam2 = 122.9 TiB [which is nearby 122 TB shown on Veeam UI]

Approx. free space:
= Approx. physical available space in DDR – (precomp size of the mtree/X)


Parameters:

Approx. physical available space in DDR = 12.88 TB which is approx.12000.64 GiB
Precomp size = 101171.1 GiB
Overall deduplication factor (X) = 10.5x

Calculations:

Approx. Free Space = 12000.64 GiB - (101171.1 GiB / 10.5)
                   = 12000.64 GiB - 9635.3 GiB
                   = 2365.3 GiB 

Approx. Free Space = 2365.3 GiB [which is 2.15 TiB and that is NOT shown as Free Space on Veeam UI]

Free Space shown on Veeam2 = Boost Calculated Value (Approx. Free space) * Total Comp Factor (Deduplication) 
                           = 2.15 TiB * 10.5x = 22.57 TiB 

Free Space shown on Veeam2 = 22.57 TiB [close to what is shown on UI - 23.1 TB]

• UI Discrepancies: Stem from whether Veeam multiplies Boost calculated values by deduplication factor (depends on postcomp comparison).
• Formulas Preserved: All calculations adhere to Data Domain’s physical or deduplication-aware logic.