A Network File System (NFS) client is part of a kernel. After you install an NFS client, errors may occur due to pre-existing bugs in the kernel. To ensure the stability of NFS, we recommend that you use the kernel versions verified by Alibaba Cloud.

Recommended Linux versions

We recommend that you use official kernel images tested and verified by Alibaba Cloud to ensure system stability. For more information, see Recommended kernel images.

NFS response errors due to a kernel bug in network stacks (priority: high)

An NFS response error may occur if the kernel version of a Linux system is in the range of [2.6.32-296, 2.6.32-696.10.1). If the NFS server is too busy to process a request within the timeout period and the request is repeatedly retransmitted, a network stack error may occur. This results in an NFS response error.

If the "operation failed" message appears, we recommend that you restart the Elastic Cloud Service (ECS) instance that hosts the client. For more information, see RHEL6.9: NFSv4 TCP transport stuck in FIN_WAIT_2 forever.

NFS response errors due to a kernel bug (priority: high)

  • An NFS response error may occur if an NFS server failover occurs when you open a connected NFS client or access a file system by using the NFS client. The failover may result in a deadlock, which may cause an NFS response error. Such NFS errors may occur in the following kernel versions:
    • RHEL 6 or CentOS 6 2.6.32-696.3.1.el6
    • RHEL 7 or CentOS 7 3.10.0-229.11.1.el7 and earlier versions
    • Ubuntu 15.10: Linux 4.2.0-18-generic

    If the "operation failed" message appears, we recommend that you restart the ECS instance that hosts the client. For more information, see RHEL7: NFSv4 client loops with WRITE / NFS4ERR_STALE_STATEID - if NFS server restarts multiple times within the grace period.

  • An NFS response error may also occur if a network partition or network jitter occurs and results in reconnections. This is because the NFS may fail to correctly process the related error codes. Such NFS response errors may occur in the following kernel versions and the bad sequence-id error keeps appearing in system logs.
    • RHEL 6 or CentOS 6 2.6.32-696.16.1.el6 and earlier versions
    • RHEL 7 or CentOS 7 3.10.0-693.el7 and earlier versions

    If the "operation failed" message appears, we recommend that you restart the ECS instance that hosts the client. For more information, see RHEL6 / RHEL7: NFS4 client receiving NFS4ERR_BAD_SEQID drops nfs4 stateowner resulting in infinite loop of READ/WRITE + NFS4ERR_BAD_STATEID.

  • If the kernel version is CentOS or RHEL 5.11.x, the NFS may respond slowly or stop responding due to a kernel bug in some cases. This error may occur if you run the ls command or a command that contains the wildcard characters * or?, or perform other operations that needs to traverse a directory.

    To fix the issue, we recommend that you upgrade the kernel to the latest version.

Unsupported chown command and system API calls (priority: low)

If the kernel version is 2.6.32, the chown command and system API calls are not supported on an NFS client.

Unable to stop an ls operation (priority: low)

If the kernel version is 2.6.32-696.1.1.el6 or earlier, the ls operation may be unable to be stopped. This may occur if you create or delete files or subdirectories when the ls command is running.

To fix the issue, we recommend that you upgrade the kernel to the latest version.