For over a decade, content creation infrastructure has been penetrated by IP-based networks and network-attached storage products. Even editorial shared storage, once the bastion of a handful of high-end facilities, has become commonplace throughout the industry with the help of network file systems and lower cost 1/10Gb Ethernet hardware and relative ubiquity of support in popular desktop operating systems.
In the move toward these networks, operators and administrators have learned to live with the challenges brought about by IP-based technology. These include dependency on external IT resources, variations in desktop OS network file system support, lack of isolation causing traffic disruptions and security concerns, and higher resource usage on desktop PCs when processing Ethernet transactions.
Are these limitations worth the benefits? Before jumping wholesale into an all-IP future, content creation professionals should consider what is lost in the move towards NAS topology, what is better achieved with a custom shared file system through Fibre Channel, and whether there is a happy medium to be found.
The Impact of Permissions and Dependency on External Resources
In the world of IP and NAS-based workgroups, solutions are designed to deploy within a set of services that manage permissions and authentication for the network. These include directory services, with which user accounts are assigned to network resources, DHCP and DNS services that manage network locations, and routing and switching that manage traffic in the facility. If there is any disruption in these services, network storage can become unavailable. Small facilities that rely on prosumer router technology and have little network experience can find problems with IP management, and will almost certainly have problems with user account setup and permissions. Login to local user accounts that are not recognized as part of a domain group can exclude the user from files, and the user may be unable to modify or delete files that are owned by user accounts that no longer exist.
In addition, access to move or write to a file on a client workstation may be determined by the state of that file on another workstation, leaving the user to change their workflow, create revisions or copies unnecessarily. Permissions on NAS resources are variable folder to folder and file to file, and are not apparent by looking at the file or folder, so operators can make errors such as mistaking a read-only location for a writable one. By the time the administrator fixes the problem, valuable time has been lost.
Alternatively, a custom shared file system with Fibre Channel or IP-based collaborative network would help alleviate this confusion. With a custom shared file system, the volume can be set to display as a local drive, appearing in the Mac sidebar for ease of navigation. Permissions are set across all local users to full read/write access or read-only access, depending on the permissions of the volume itself.
OS Interoperability Dependency is Often Overlooked
As operating systems advance and take different approaches to network interoperability, network storage in the facility is at risk of being left out of the compatibility matrix.
This is especially damaging when facility workstations use different versions of the Mac OS, some supporting newer, more stable versions of the SMB code, some with older and broken versions. The workflow of a facility sometimes hinges upon older systems, with hardware that may not be supported in new OS versions but is still integral to the project. Artists have their preference of software applications, and sometimes that application is only supported on older OS revisions. For example, many facilities still use the Final Cut Pro Studio product in 2019 – ten years after the final release of that software.
When using a custom shared file system, whether connected through Fibre Channel or Ethernet, the list of compatible OS versions is more complete, sometimes reaching back through several years of OS revisions. This is possible because with a custom shared file system, the client OS is not the owner of the storage volume, nor does it play as integral a part in the exposure of the volume to the desktop. This helps maintain a consistency of functionality across multiple workstations running various OS versions.
Performance is More Than Just Benchmarks
Performance in general is a measure of how well a job is being done. High-performance NAS systems may be fast in benchmark tests, but that doesn’t tell the whole story. The job may still be done poorly, even with systems that display high-speed metrics. The reasons for this can be various, including issues with permissions and interoperability that were mentioned earlier. Many times, however, the performance of a network storage system is limited by the network protocol itself.
TCP-IP protocol consists of several layers – the actual data payload among them – which includes additional headers containing client IP and TCP data. These layers must be processed by the client and server whenever there is a request for data. The maximum size of a payload in standard Ethernet protocol is 1500 bytes, or 1.5KB. Jumbo frames can produce payloads up to 9000 bytes each, or 9KB, but jumbo frames are not compatible with every switch infrastructure. It only takes one switch in the facility to fail compatibility, and the connection will drop.
As an example of the additional processing required for video, up to 160,000 Ethernet frames per second must be processed in a 4-way multi-camera timeline. This affects CPU usage on the client and server side. When the client count is scaled, the processing required to service all the client workstations becomes a limiting factor.
Measure Your Network in the Real World
Client workstation CPU load is a common cause of poor video playback. If you consider all the intensive decompression and display processing needed to play video, you can see why the CPU level is constantly a concern on content creation workstations. If it’s possible to lower the CPU usage, video will play more smoothly, and applications may not require draft mode settings for video display. Fibre Channel block-mode offers this type of low-CPU overhead and that can be a real benefit.
An example of this can be seen simply by measuring the CPU usage required to achieve a certain bandwidth over an ethernet connection, and compare that to the same bandwidth through Fibre Channel. As a ratio of CPU usage to bandwidth, Ethernet commonly requires several times the CPU to achieve the same data transfer speeds. The CPU cycles being used for file access through the IP network restricts the CPU available for the application. This is why NAS looks very good on a benchmark, but fails to perform in real-world video workflows.
Bonus – Fibre Channel Avoids Restrictive Security Policies
Facilities have new priorities in the age of information accessibility; some of these priorities center on restricting access to your secure information, and protecting the integrity of the data and network. To this end, IP networks are under severe scrutiny. IT professionals know that there are many ways to gain access to your desktop via IP network, but no way to do it through point-to-point Fibre Channel connection methods. Because of this, most IT departments are happily ‘hands-off’ when your system is attached to a central server through Fibre Channel. But be careful, some traditional SAN environments have requirements of both Fibre Channel and Ethernet for connected workstations. Be sure to investigate all the connectivity requirements.
Best of both worlds?
The technology of collaborative storage systems continues to follow the trend of IP-based topologies because of the wide accessibility and low cost of scale-out hardware and systems. However, for facilities looking to maximize their spending on future-proof connectivity, the value of dedicated, purpose-built networks for high-bandwidth data access can’t be overlooked. As important as NAS can be for unlimited access to company data, investing in NAS alone can leave a facility spending more in supplementary storage to offload network traffic.
Content creation professionals need to look at shared storage options that take advantage of both the scale-out architecture of NAS and the dedicated low-latency design of Fibre Channel on the same turnkey server. These connectivity methods are complementary – they can be used in parallel, and even in failover scenarios. For example, Facilis Technology has partnered with ATTO Technology to offer shared storage solutions with Fibre Channel and Ethernet connectivity through a custom shared file system, for the benefit of the content creator, facility owner and engineer.
As client-side bitrates increase due to higher quality imaging and aggressive broadcast requirements, limitations will inevitably appear in even the strongest NAS architecture. A combined Ethernet-Fibre Channel approach can create a far more efficient system that uses the best of both technologies.