Upgrading vCenter Server fails at Stage2 - "Insufficient space on the source export partition '/' to accommodate all the data for upgrade data"

Products

• VMware vCenter Server

Issue/Introduction

• While performing the upgrade of vCenter from 6.x to 7.0.x or 8.0.x, an issue might be encountered in stage 2: “Insufficient space on the source export partition ‘/’ to accommodate all the data for upgrade data"
  
  
• /var/log/vmware/upgrade/export-upgrade-runner.log

YYYY-MM-DDTHH:MM:SS INFO upgrade.states.component_states vcdb:Export: reported message 'Exporting VMware vCenter Server Database data...'
YYYY-MM-DDTHH:MM:SS INFO upgrade.states.component_states vcdb:Export:

YYYY-MM-DDTHH:MM:SS INFO upgrade.states.component_states vcdb:Export: YYYY-MM-DDTHH:MM:SS INFO vcdb.const Exporting core tables...
YYYY-MM-DDTHH:MM:SS INFO upgrade.states.component_states vcdb:Export: didn't have progress. Next report will come after 60 seconds
YYYY-MM-DDTHH:MM:SS ERROR status_reporting_sdk.filelock Got OS error: [Errno 28] No space left on device: '/usr/lib/vmware/cis_upgrade_runner/cis-export-folder/system-data/cis_upgrade_data.sfe.upgradeLock'

• This error message is displayed when any option is selected as shown below:

Cause

This occurs when there is an insufficient space in the root partition. 

Resolution

To resolve this issue, follow the below steps

• Connect to the source vCenter Server Appliance through SSH. For more information, see Enable or Disable SSH and Bash Shell Access
• Log in as root.
• Run command "df -h", to find which directory has enough space to so that the files can be saved for export.

Below is the sample output 

Filesystem	Size	Used	Avail	Use%	Mounted on
devtmpfs	4.9G	0	4.9G	0%	/dev
tmpfs	4.9G	20K	4.9G	1%	/dev/shm
tmpfs	4.9G	660K	4.9G	1%	/run
tmpfs	4.9G	0	4.9G	0%	/sys/fs/cgroup
/dev/sda3	11G	5.3G	4.7G	53%	/
tmpfs	4.9G	232M	4.7G	5%	/tmp
/dev/sda1	120M	35M	80M	30%	/boot
/dev/mapper/seat_vg-seat	9.8G	337M	8.9G	4%	/storage/seat
/dev/mapper/imagebuilder_vg	9.8G	23M	9.2G	1%	/storage/imagebuilder
/dev/mapper/db_vg-db	9.8G	157M	9.1G	2%	/storage/db
/dev/mapper/autodeploy_vg	9.8G	32M	9.2G	1%	/storage/autodeploy
/dev/mapper/core_vg-core	25G	106M	24G	1%	/storage/core
/dev/mapper/updatemgr_vg	99G	415M	93G	1%	/storage/updatemgr
/dev/mapper/log_vg-log	9.8G	1.5G	7.8G	16%	/storage/log
/dev/mapper/dblog_vg-dblog	15G	150M	14G	2%	/storage/dblog
/dev/mapper/netdump_vg	985M	1.3M	932M	1%	/storage/netdump

• Once the directory is selected e.g /storage/core (which has 24 GB free), in the installer, Export directory section type: /storage/core and click Next. 
• Follow the instructions to complete the upgrade process.

The new partition, which is mentioned in the Export directory section, the vCenter will save its data while migrating contents from source vCenter server to the target vCenter server.

Additional Information

For information refer : List of VMDKs/Partitions for a vCenter Server 8.0 - Size Mount point and Purpose