Something doesn't seem right here. 100 viewers x 1 GB each requires a transfer of 100 GB in less than an hour.
An ordinary SATA disk can easily do 100 MB/second so transferring 100 GB will take 1000 seconds or 16 minutes. What's the disk going to do with the rest of the time? I'd say £100 is more like it. Hank On Thu, May 3, 2012 at 11:09 AM, Leslaw Zieleznik <[email protected]>wrote: > > We have discussion today about the shared volume storage that can also > support streaming. > And the conclusion was that to support 100 streams (1GB/hour high > resolution recordings) played at the same time, > we need a high-performance disk RAID array which may cost at least £20k or > rather £50k. The calculation is shown below. > > Therefore my question is, whether there is any escape from purchasing such > an expensive storage? > > Many thanks, > Leslaw > > And here is the calculation. > Take the case of video encoded at 1GB/hour, equal to 300KB/s, stored on > a standard disk array with 4KB blocks. A single "viewer" will require > the disk to sustain 300/4 = 75 IOPS (I/O operations per second). > 100 streams served simultaneously will require 100 times as much I/O, i.e. > 7,500 IOPS. A typical 7200rpm disk can sustain at most 150 IOPS (i.e. two > streams); > a typical 5-disk RAID5 array (e.g. five 2TB 7200rpm disks) would support > perhaps 150*4 = 600 > IOPS i.e. just 8 streams! > So the solution is a high-performance RAID array. > >
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