FAQs

1. How do I handle an I/O timeout when I use KFS?

A Kingsoft Cloud Elastic Compute (KEC) instance connects to a Kingsoft Cloud File Storage (KFS) file system over an endpoint subnet in a virtual private cloud (VPC). The I/O performance is limited by the internal network throughput of the KEC instance and the performance of the KFS file system. The internal network throughput of a KEC instance depends on the purchased package. A larger package supports a higher throughput. If you need a high throughput, upgrade the specifications of your KEC instance. For more information, see Instance types.

2. How does KFS charge fees?

KFS charges fees based on your peak storage usage per hour.

3. What access protocols are supported by KFS?

KFS supports NFS 3.0, CIFS, SMB 2.0, SMB 2.5, and SMB 3.0.

4. How can I ensure data consistency when multiple applications read data from or write data to one file?

We recommend that you lock the file when one application is accessing the file so that other applications cannot modify the file at the same time.

5. What ports need to be opened for a KFS file system?

6. What can I do if a KFS file system cannot be mounted?

• Check the error message.
• Check whether tools such as nfs-utils, nfs-common, and cifs-utils are installed.
• Check whether the local mount directory exists.
• Check whether the file system and the KEC instance reside in the same VPC and region.
• Check whether a security group policy that prohibits access to external ports is applied to the KEC instance.

7. Why does the NFS client in Linux fail to reach the expected performance?

Possible cause: In Linux, the number of concurrent NFS requests that are allowed on the NFS client is limited. The number of concurrent NFS requests is set to 2 in the kernel that is compiled in default settings. This seriously affects the performance of the NFS client. Solution: After you install the NFS client, modify the number of concurrent NFS requests to improve the performance of the NFS client. Procedure:

1. Install the NFS client.

2. Run the following commands by using an account with the root privileges to modify the number of concurrent NFS requests to 128:

   echo "options sunrpc tcp_slot_table_entries=128" >> /etc/modprobe.d/sunrpc.conf
   echo "options sunrpc tcp_max_slot_table_entries=128" >>  /etc/modprobe.d/sunrpc.conf

3. Restart the KEC instance.
4. Run the following command to verify that the modification takes effect. If the returned value is 128, the modification is successful.

   cat /proc/sys/sunrpc/tcp_slot_table_entries