Avamar: Checkpoint fails with result MSG_ERR_DDR_ERROR due to Data Domain capacity issues

Both scheduled and manual checkpoints are failing with MSG_ERR_DDR_ERROR.

For example:

status.dpn

Mon Aug 19 13:33:53 WEST 2019  [AV-XXX] Mon Aug 19 12:33:53 2019 UTC (Initialized Wed Feb 11 12:42:51 2015 UTC)
Node   IP Address     Version   State   Runlevel  Srvr+Root+User Dis Suspend Load UsedMB Errlen  %Full   Percent Full and Stripe Status by Disk
0.0     10.xxx.x.xx  19.1.0-38  ONLINE fullaccess mhpu+0hpu+0hpu   1 false   0.3 0 31802 52675327  11.8%  12%(onl:4148) 11%(onl:4133) 11%(onl:4135) 11%(onl:4140)  11%(onl:4138) 11%(onl:4147)
Srvr+Root+User Modes = migrate + hfswriteable + persistwriteable + useraccntwriteable

System ID: XXXXXXXX@00:1E:67:87:C4:6B

All reported states=(ONLINE), runlevels=(fullaccess), modes=(mhpu+0hpu+0hpu)
System-Status: ok
Access-Status: full

Checkpoint failed with result MSG_ERR_DDR_ERROR : cp.20190819054530 started Mon Aug 19 06:45:31 2019 ended Mon Aug 19 06:58:24 2019, completed 24840 of 24841 stripes
Last GC: finished Mon Aug 19 05:21:35 2019 after 20m 58s >> recovered 71.89 MB (MSG_ERR_DDR_ERROR)
Last hfscheck failed with result MSG_ERR_DDR_ERROR : started Mon Aug 19 05:34:23

The Data Domain log (/usr/local/avamar/var/ddrmaintlogs/ddrmaint.log) reports an "I/O error":

grep -i Error /usr/local/avamar/var/ddrmaintlogs/ddrmaint.log|grep -v -i "Error not set"

Aug 19 05:15:50 av-XXX ddrmaint.bin[49665]: Error: <4710>Datadomain garbage collect operation failed.
Aug 19 05:34:18 av-XXX ddrmaint.bin[52434]: Warning: Calling DDR_CREATE_SNAPSHOT returned result code:5009 message:I/O error
Aug 19 05:34:18 av-XXX ddrmaint.bin[52434]: Error: cp-create::execute_create_checkpoint - Failed to create checkpoint for avamar-XXXXXXX to snapshot cp.20190819042140 on ddXXX, DDR result code: 5009, desc: I/O error
Aug 19 05:34:18 av-XXX ddrmaint.bin[52434]: Error: <4760>Datadomain checkpoint create operation failed.

The Data Domain (DD) space has reached capacity.

This can be verified by doing the following:

1. Connect to the Data Domain. Use Avamar: How To Access a Data Domain System as a reference as required.

2. Check for any alerts:

alerts show current

Id      Post Time                  Severity   Class        Object          Message
-----   ------------------------   --------   ----------   -------------   ----------------------------------------------------------------------------
p0-87   Fri Aug 16 21:55:33 2019   CRITICAL   Filesystem   FilesysType=2   EVT-SPACE-00004: Space usage in Data Collection has exceeded 100% threshold.
-----   ------------------------   --------   ----------   -------------   ----------------------------------------------------------------------------
There is 1 active alert.

3. Run the "df" command:

df

Active Tier:
Resource           Size GiB   Used GiB   Avail GiB   Use%   Cleanable GiB*
----------------   --------   --------   ---------   ----   --------------
/data: pre-comp           -       15.1           -      -                -
/data: post-comp    30731.1    30608.8       122.3   100%             13.1
/ddvar                 49.1        8.7        37.9    19%                -
/ddvar/core           158.3        0.1       150.2     0%                -
----------------   --------   --------   ---------   ----   --------------
 * Estimated based on last cleaning of 2019/07/15 06:04:40.

Cloud Tier
Resource           Size GiB   Used GiB   Avail GiB   Use%   Cleanable GiB
----------------   --------   --------   ---------   ----   -------------
/data: pre-comp           -       19.0           -      -               -
/data: post-comp   33487.7*       20.4     33467.4     0%             0.0
----------------   --------   --------   ---------   ----   -------------
* Post-comp size is based on CLOUDTIER-CAPACITY license and might not be same as the cloud storage.

Total:
Resource           Size GiB   Used GiB   Avail GiB   Use%   Cleanable GiB
----------------   --------   --------   ---------   ----   -------------
/data: pre-comp           -       34.1           -      -               -
/data: post-comp    33829.9       36.4     33793.4     0%             0.0
/ddvar                 49.1        8.7        37.9    19%               -
/ddvar/core           158.3        0.1       150.2     0%               -
----------------   --------   --------   ---------   ----   -------------

1. On Data Domain:

a. Check the file system cleaning status:

filesys clean status 

Example outputs:

Cleaning is not running:

Cleaning finished at 2019/08/19 21:37:46

Cleaning is running:

Cleaning started at 2019/08/19 06:00:02: phase 3 of 6 (pre-enumeration)
  1.6% complete,     0 GiB free; time: phase  1:26:05, total  1:48:11

b. If cleaning is running, wait for it to complete and then check the capacity using the df command.

c. If cleaning is not running, check the file system cleaning schedule:

filesys clean show schedule

Example output:

Filesystem cleaning is scheduled to run "Tue" at "0700".

d. If required, start a manual file system clean, and monitor to completion using the "fileysys clean watch" command as indicated in the output below.

filesys clean start

Cleaning started.  Use 'filesys clean watch' to monitor progress.

2. On Avamar:

a. Once the capacity issues on Data Domain have been resolved, perform a manual checkpoint:

mccli checkpoint create --override_maintenance_scheduler

b. Monitor to completion, and verify that it is successful.

c. Monitor the grid through the next maintenance window to verify that all Avamar maintenance tasks (checkpoint, checkpoint validation, (hfscheck) and garbage collection complete successfully.