About Storage - General Considerations for playout and ingest solutions

When  talking about ingest and playout software, the question about which storage to use is one of the most important if you want to have a reliable playout or recording solution.

Softron solutions can work with any type of storage. As long as the volume is mounted on your Mac, we will be able to read from it or write to it. But there are simple considerations to have the safest operation possible:

• Avoid using the boot drive (usually named Macintosh HD). If this may work most of the times, it is a volume where the Mac OS system read or write very frequently and thus can have drops in its read/write performance. This is specially true for our recording solutions like MovieRecorder.
• Make sure the disk you are recording to or reading from has enough read/write performance for the format/codec you are using. There are free software that can measure the preformance of your disk and tell you if it can sustain the datarate. Like for example the Blackmagic Disk Speed Test or the AJA System Test. 
• When you are running tests to see how much you can get out of a storage, remember that it's very difficult to measure the constant bandwidth available. Drives may be going slower for some reasons for a very short time (caches flush, ...).  Monitoring the disk activity for a longer period will give you a better insight then just a few seconds of monitoring. But it may be very difficult to get a perfect idea of the long term performance as some disk systems (specially the ones working with RAID controllers) will do some maintenance operations at given times (usually at night).
• Make sure that there is no cache on your storage. Indeed, cache is very optimised for short read or write session. But if you read or write constantly from/to that storage, and particularly for constant writing, cache must not be used. Indeed, at first the write speed will be very fast, but once the cache is full, the storage will have to empty its cache, and when it does that, write performances go down; and sometimes it even blocks and does not write at all anymore. Some storage allow to disable the cache, when it's software configurable, but sometimes the cache is built in the hardware, and there is no way to disable it. Some SSD for example have a cache that can not be disabled. So make sure to check this before using these.
• Performances of of your storage are at best when it is empty, but performance will go down when it fills up. If the available space gets really low, you may see a very big drop in performance. This is specially true with RAID systems. And it's easy to understand: when the disk is empty, the system can write wherever it wants, but when it's full, it has to "search" for available space and fragment the data in different blocks. OnTheAir Node, OnTheAir Video and MovieRecorder have a buffer (a few seconds) so you can have a temporary drop of performance, but it can not be repeated over time nor constant.
• Check which codec, frame size and frame rate you are using as it will impact greatly with the data rate required for the storage. You can check the data rate needed for your codec, frame size and frame rate with the AJA DataCalc application for example.
• Remember that even if audio doesn't use a lot of bandwidth, audio is using some bandwidth. If you record/play 16 channels at 48K-16bit, you will need 1.5 MB/sec per stream only for the audio.This is not a lot in todays world but still something to consider.
• If you play or record multiple streams on your storage (from the same computer or different ones if you use a shared storage) remember to consider all the streams. For example if you record 4 streams of 1080i29.97 Apple ProRes (HQ) to a shared storage, you will need around 130 MB per second. If in the edit suites your editor are editing at the same time and reading the 4 streams at the same time (if they use multiclips for example), your storage will have to deliver 130 MB per second more, so a total of 260 MB/sec.
• Remember that there are other operations that can take the bandwidth of your storage. Like if you duplicate a large clip with the Finder, the Finder will try to copy it as quick as it can and take as much read/write it can from the disk where the clip is and thus it may not leave enough bandwidth for you to record or play what you need from that disk. Make sure you don't do operations that will use high bandwidth.
• If you can not record or read from a storage, check that you have read/write access to it.
• And last but not least, remember that no storage solution is eternal. If working on important material, you should make sure to have a regular backup of your data. Even if you are working with RAID 5 for example, this will protect you against one failed hard drive (not two) but it doesn't protect you against an accidental delete of a file for example.

Finally, remember that the Softron resellers and integrators can advise you with the best solution that will fit your needs. There are Softron resellers and integrators all around the world that can provide a local support and professional advises. Check the list of Softron resellers on the website.