System congestion
Possible congestion issues in the Content Software for File system are described.
Overview
The Content Software for File system is built to be very efficient, provide maximum performance and saturate the network links.
In some situations, the system itself may slow down IOs when reaching some limits (or even block new IOs at higher limits) until the congested resource is relieved. Such situations may be transient and the issue will be resolved on its own after a short time. However, there are also cases that suggest an issue that needs to be addressed, such as a workload maxing out the resources of the cluster. In such cases, the cluster resources must be expanded, as described in Expanding and shrinking cluster resources. For more information contact customer support.
System congestion events or alerts
The Content Software for File system can issue several types of congestion events/alerts:
| Type | Description | Actions |
| FIBERS | Extreme load of concurrent system operations on a node. | This is usually a transient situation due to load on them system. If the load is consistent and the problem persists, add more resources (hosts/cores), as described in Adding a backend host or Addition of CPUcores. |
| DESTAGER | Too many pending IOs are waiting to be written for a specific node. | This is usually a transient situation due to load on them system. If the load is consistent and the problem persists, add more hosts to the cluster as described in Adding a backend host or expand the host resources as described in "Expansion of specific resources" in the Content Software for File Command Line Reference. |
| SSD | Too many pending IOs to the SSD. | If there is a single SSD, it is probably faulty and needs to be replaced. If there are multiple SSDs, the load on the system is too high. To handle such a load, more SSDs should be added to the system, as described in Expansion of specific resources. |
| RAID_NOT_OK | More IO failures than can be handled have occurred, and IOs cannot be served. | Make sure to bring up any host that might be down. If all hosts are up, contact customer support. |
| XDESTAGE | Auxiliary cluster resources are low. | This is usually a transient situation due to load on the system. If the load is consistent and the problem persists, add more hosts to the cluster as described in Adding a backend host or contact customer support. |