Data Domain: STORAGE-00025: Current cache tier size is less than what the system is licensed for

Summary: This article describes the cause of and resolution for the alert "EVT-STORAGE-00025: Current cache tier size is less than what the system is licensed for".

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Symptoms

  • Alert EVT-STORAGE-00025 appears on a Data Domain system.
  • The system is licensed for a cache tier, but:
    • No cache tier exists, or
    • The cache tier is smaller than the licensed size.

About Cache Tier (DDOS 6.0 and later):

  • Consists of dedicated SSD devices installed in the head unit or dedicated, attached shelf (depending on platform)
  • Stores DDFS metadata to improve performance.
  • Supported only on specific platforms (refer to the Administration Guide for your DDOS version).

Example alert:

Id      Post Time                  Severity   Class             Object                Message                                                                                 
-----   ------------------------   --------   ---------------   -------------------   ----------------------------------------------------------------------------------------
m0-2    Mon Jul 18 13:49:28 2016   WARNING    Storage                                 EVT-STORAGE-00025: Current cache tier size is less than what the system is licensed for.

Cause

The alert occurs when:

  • The system is licensed for a cache tier of a certain size, but:
    • No cache tier exists, or
    • The current cache tier size is smaller than the licensed size.

Resolution

  1. Step 1: Verify Cache Tier License

    In DD-CLI (ssh), run: # elicense show

    # elicense show
...
Capacity licenses:
##  Feature              Shelf Model   Capacity    Mode        Expiration Date
--  ------------------   -----------   ---------   ---------   ---------------
...
3    SSD-CAPACITY        n/a           2.91 TiB    permanent   n/a
--  ------------------   -----------   ---------   ---------   ---------------
    • Here, the system is licensed for 2.91 TiB of cache tier.

     

  2. Step 2: Check Current Cache Tier Size

    Run: # storage show all

    # storage show all
...
Cache tier details:
Disk          Disks     Count   Disk         Additional
Group                           Size         Information
-----------   -------   -----   ----------   -----------
(available)   1.5-1.8   4       745.2 GiB
-----------   -------   -----   ----------   -----------

Current cache tier size: 0.0 TiB

    In this example:

    • Licensed size: 2.91 TiB
    • Current size: 0.0 TiB
    • Four SSDs are available for cache tier (totaling 2.91 TiB)

     

  3. Step 3: Add Disks to Cache Tier

    Run: # storage add disks <n.n> tier cache

    # storage add disks 1.5,1.6,1.7,1.8 tier cache
    • This creates or expands the cache tier. The alert clears once the cache tier matches the licensed size
 
NOTE: Populating the cache tier with DDFS metadata occurs in the background. Full performance benefits are realized after population completes.

Additional Information

Sometimes, adding a disk to the cache tier may fail with the message:

**** Disk <disk-id> is already available.

Workaround:

  1. Remove the disk logically: 
    • # storage remove disk <disk-id>
  2. Verify disk state 
    • # disk show state
    • Cache Disk should show as Unknown (U).
  3. Add the disk back to the cache tier: 
    • # storage add disks <disk-id> tier cache
  4. Confirm the cache tier size: 
    • # storage show tier cache
    • After re-adding, the disk will join the cache tier and the size will update accordingly.

Affected Products

Data Domain

Products

Data Domain
Article Properties
Article Number: 000029068
Article Type: Solution
Last Modified: 12 Jan 2026
Version:  5
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