Introduction to the use of NFS file formats

We once learned about NFS. We have learned that this protocol and system have very important applications in network sharing. Therefore, it also has many applications in network storage. Here we will mainly explain the problem of NFS file format. We use the vmwarevm for data management. Do you know whether NFS can be applied in the vmwarevm? This article gives a detailed explanation of this issue. VMware 3.x can host the vmwarevm image file (VMDK) in the NFS file format installed in the file system. Although the process is slow, NFS has been widely used in the VMware storage industry. However, there are still some bad ideas about NFS that readers have to check.

First of all, this is not a debate over the IP protocol over optical fiber channels. It is actually an NFS debate over VMFS. To be exact, it is not a debate between NFS and VMFS. NFS is only a transmission protocol, which is actually a debate between VMFS and the file system of a specific NAS. Each NAS vendor, such as EMC, NetApp, and ONStor, has its own file system. Compared with VMFS, these file systems have their own advantages and disadvantages. Due to the inherent sharing feature of NAS, most vendors have configured some common features in their respective file systems.

VMFS is a file system provided by VMware in the module system for hosting Virtual Machine images. It can be shared and clustered on the SAN. It has powerful functions, but as a file system, it also has its own shortcomings. NFS can solve those problems. The NFS file format and its NAS are shared devices. VMDK is actually a file, so it is not a big change to regard it as something that serves files for certain tasks.

Although VMware ing on NFS is a daily task, it is not the easiest environment. Creating and preparing VMware databases and configuring VMotion with NFS-based services are simple. It's easy to resize them without interrupting the services of virtual machines. On the contrary, most VMware administrators suspend virtual machines for the sake of insurance when using VMFS. Regardless of the preventive measures taken, narrowing down the database size may lead to major problems. Experts generally do not recommend that users do this.

In fact, the NFS file format is an IP-based protocol, but not an IP-based storage protocol. Therefore, it can greatly simplify work and reduce costs. However, the plan cannot be completely abandoned. If the performance problem becomes more and more serious, you must adjust the IP infrastructure. The complexity of relevant work is no less complex than that of the optical fiber channel.

Using IP addresses is more likely to encounter performance problems than using fiber-optic channels, because many infrastructures are still built on 1 GB Ethernet. 10 GB Ethernet can solve many performance problems, but so far, the standard 10 GigE NIC in VMware hosts can only make full use of 40% to 50% of the available bandwidth, mainly because the problem of command queuing is not solved. To solve this problem, VMware developed the NetQueue technology. When NetQueue is integrated with support cards from Intel, Neterion, Solarflare, and other vendors, it can basically reach the full-line speed. These will increase the cost and complexity of the work, and further weaken its advantages.

NFS/NAS and VMware have other problems. You cannot directly start ESX servers with virtual machines. Therefore, if you want to start various devices from shared storage, you must use another protocol. Secondly, it does not support RDM, so it does not support Microsoft ters TERs. If this is important to you, you must also use other protocols. Finally, until now, NFS support seems to be the latest VMware features in Storage VMotion, Site Recovery Manager, and other products.

We believe that the NAS/NFS file format is very suitable for Working Loads with medium and low I/O requirements, while the Optical Fiber Channel is suitable for Working Loads with medium and high levels of I/O requirements.