Understanding Portmap with NFSv3 and Port 111

Portmap is a service that converts RPC program numbers into protocol port numbers. It must be running in order to make RPC calls. Portmap makes the dynamic binding of remote programs possible. NFSv3 is based on portmap. We will dive into this today. How Portmap works? The portmap service maps RPC service and version numbers […]

Understanding Rpcbind and RPC and Port 111

The rpcbind is a utility that converts RPC program numbers into universal addresses. It must be running on the host to be able to make RPC calls. We will dive into RPCbind today to see how it works. Understanding RPC Remote Procedure Call (RPC) is an inter-process communication technique to allow client and server software […]

Check NFS Port 2049 With Examples

Network File Sharing (NFS) is a protocol that allows us to share directories and files with other Linux clients over a network. The ports for NFS are confusing for many people. We will deep dive into this today. NFSv3 Port NFSv4 Port NFSv3 Port NFSv3 and NFSv2 include portmapper, nfsd, and other NFS services like […]

Quick Guide to Fix Linux IOWait Issue

Linux high IO wait is a common Linux performance issue. Today we will look at what io wait means and what contributes to this problem. Hope this can give you more ideas about how to fix high IOwait issue. What is Linux IO wait? Determine if an IO problem is causing the system to slow […]

What does Timeo mean during NFS mount timeout in Linux?

Timeo is a timeout mount option in NFS mount. It is the timeout value that the NFS client uses to wait for a response before it retries an NFS request. Let’s dive into the details about what this timeout value means between NFS over TCP and NFS over UDP. Check this post to learn more […]

10 important Linux File System Terminology and Concepts

File system is an important part of Linux world. We collect 10 useful file system concepts below to help you understand what file system is. Important File system Concepts File system: An organization of data as files and directories, with a file-based interface for accessing them, and file permissions to control access. Additional content may […]

Linux File System: Raw IO and Direct IO

Raw IO and Direct IO are both bypassing file system cache. Here are more details about these two IOs. This can help us understand the difference and troubleshoot easier when we get a file system issue. Difference Between RAW IO and Direct IO Raw I/O is issued directly to disk offsets, bypassing the file system […]

How to Check if a Disk is Busy in Linux

Disk utilization in iostat command is a key metric to check if a disk is busy or not in Linux. It is used to calculate the time percent that a disk was busy actively performing work during an interval. Hope this post can help you find out which disk is busy. What is disk utilization […]

What is IOwait on Linux

Linux IOwait is a common Linux performance issue. Today we will look at what iowait means and what contributes to this problem. Hope this can give you more ideas about high IOwait issue. IOwait on Linux The iowait column on top command output shows the percentage of time that the processor was waiting for I/O […]

How to Check HBA WWN WWNN WWPN on Linux?

How to get HBA WWPN on Linux is a common task for a storage engineer. We need the WWPN to configure zone on the switch side.We will look at this question today. In our SAN environment, we have two HBAs installed on the Linux system. We can get the HBA WWN/WWPN using the following way […]