ESXi host RAM disk is full

Products

• VMware vSphere ESXi

Issue/Introduction

One of the RAM disk that make up the ESXi host root file system might reach its resource pool limit as a result of a software failure or an accidental use of an incorrect path.

 

Example

When an administrator manually copies files to the host and accidentally uses an incorrect path (that is, one outside /vmfs/volumes), the following error message appears:

The ramdisk 'root' is full. As a result, the file /testfile could not be written.

In the /var/log/vmkernel.log file, the following message may also appear.

VisorFSRam: 233: Cannot extend visorfs file /var/lib/vmware/hostd/journal/ because its ramdisk (root) is full.

Impact

Files on the affected RAM disk can no longer be extended.

Various administrative actions depend on the ability to write files to various parts of the root file system and may fail if a RAM disk is full.

Resolution

To view and identify large files larger than 1 MB, review the below steps:

1. SSH to the affected ESXi host
2. To view the ramdisk, run:
   
   vdf -h
   
   
3. Identify files in the root directory larger than 1 MB:
   
   find / -size +1024k -exec du -h {} \; | less
   
   
4. Old/stale leftover ESXi host log bundles should be copied/moved off and removed to provide space back to the ESXi host.

If the error was caused by an administrator action, delete the files that use the incorrect path or move them to a datastore.

Additional Information

For additional information:

• Investigating disk space on an ESX or ESXi host
• Creating a persistent scratch location for ESXi 8.x/7.x/6.x
• ESXi host becomes unresponsive when attempting a vMotion migration or a configuration change
• The /var/log/wtmp file grows rapidly and fills the ramdisk of the ESXi host
• ESXi RAM disk full due to a locked virtual machine log file