Resource Considerations

Every a9s Data Services Service Instance has an a9s Parachute process running. This process will stop the node process when the persistent disk hits the configured usage limit (default: 80%). This is valid for all Services.

The persistent disk is mounted using the ext4 file system, that reserves a portion of the file system (5% by default) for the root user to prevent, among other things, normal users (e.g. vcap) from filling the disk and crashing the system. Additionally, some Data Services like, but not limited to, a9s LogMe2 have their own in-build safeguards against filling up a disk completely. Also, any non-root processes (e.g. postgres, logstash..) may stall when the disk is almost filled. Therefore, anything above 90% is considered unsafe and could lead to a system crash. You should instead consider using a bigger disk.

The calculation for the used disk space does not consider the reserved disk space, and it is calculated over the overall disk usage.