Media write error (84) if due to a full local cache directory
One possible cause for a media write error (84) in a Cloud Catalyst environment is described in the following topic.
The administrator configures a local cache directory as part of configuring a Cloud Catalyst storage server. Cache eviction is triggered when data causes this directory to reach the high watermark setting (HighWatermark). Once the high watermark is reached, data is purged when the used space reaches the midpoint between HighWatermark and LowWatermark (high+low)/2 and continues until LowWatermark is reached. If the rate of incoming data exceeds the rate where the watermark can be maintained, the jobs begin to fail. In this situation, the directory does not have enough space for new files and the MSDP write operation fails with a media write error (84).
This error is more likely to occur when a relatively small disk is used for demonstration or proof-of-concept testing. To prevent this error in a production environment, make sure that there is at least 4 TB of disk space available for the cache. Make sure that the cache is located on a dedicated file system that is used only for the Cloud Catalyst local cache.
After receiving a media write error (84) and addressing the cause, restart all NetBackup services to avoid a media open error (83).
The UNIX df command can be used to determine the disk space in the local cache directory. For example:
df /esfs Filesystem 1K-blocks Used Available Use% Mounted on /dev/loop0 1007896 1007896 0 100% /esfs
See the following topic for more information about Cloud Catalyst local cache considerations: