StorNext File System Tuning
The Distributed LAN (Disk Proxy) Networks
The dircachesize option sets the size of the directory information cache on the client. This cache can dramatically improve the speed of readdir operations by reducing metadata network message traffic between the SNFS client and FSM. Increasing this value improves performance in scenarios where very large directories are not observing the benefit of the client directory cache.
SNFS External API | The SNFS External API might be useful in some scenarios because it |
| offers programmatic use of special SNFS performance capabilities such |
| |
| as affinities, preallocation, and quality of service. For more information, |
| see the Quality of Service chapter of the StorNext User’s Guide API Guide. |
The Distributed LAN (Disk Proxy) Networks
| As with any client/server protocol, SNFS Distributed LAN performance is |
| subject to the limitations of the underlying network. Therefore, it is |
| strongly recommended that you use Gigabit (1000BaseT) for Distributed |
| LAN traffic. Neither TCP offload nor jumbo frames are required. |
|
|
Hardware | SNFS Distributed LAN can easily fill several Gigabit Ethernets with data, |
Configuration | so take special care when selecting and configuring the switches used to |
| interconnect SNFS Distributed LAN clients and servers. Ensure that your |
| |
| network switches have enough internal bandwidth to handle all of the |
| anticipated traffic between all Distributed LAN clients and servers |
| connected to them. |
| A network switch that is dropping packets will cause TCP |
| retransmissions. This can be easily observed on both Linux and Windows |
| platforms by using the netstat |
| progress. Reducing the TCP window size used by Distributed LAN might |
| also help with an oversubscribed network switch. The Windows client |
| Distributed LAN tab and the Linux dpserver file contain the tuning |
| parameter for the TCP window size. Note that Distributed LAN server |
| remounts are required after changing this parameter. |
20 | StorNext File System Tuning Guide |
