Home media server bandwidth issues
Discussion
Hi All
I'm having some grief with my home media server network and I thought I'd throw it out here to see if anyone can offer some insight.
Basically I've got a NAS with all my DVDs and BDs ripped into MKV format, and a number of media player devices attached to various screens around the house. Any one device can stream a BD film fine; start another stream concurrently and one of them will get choppy in playback. Start another stream and it's choppy all round.
The streamers are all Kodi boxes running OpenElec latest version - either Amazon Fire TV 4K players or self-build boxes built on Intel NUC. All are wired Gigabit Ethernet. Network switches (there are a few around the house) are medium end Cisco SG110-16 units that can support Gigabit ethernet on multiple channels concurrently (i.e. not cheapo units which have switching bandwidth issues). The NAS server I had running was a 1U Dell server with DAS in a Dell MD1000 disk array with 15x2Tb disks hardware RAID 5, running nas4free (BSD).
The NAS can sustain 85Mbps reading and writing across the network via e.g. Windows file copy of one of the MKV files (i.e. limited by the Gigabit network). Observing network utilisation when playing back the same file shows very peaky bandwidth usage about 5Mbps max for a BD image. Running a second streamer (when it gets choppy) shows network utilisation to about 9Mbps, running a third gets it to about 10Mbps.
I swapped out the NAS for something a bit lower end - an HP microserver with 4x4Tb disks software RAID with ZFS. This could sustain about 54Mbps for single file copy but showed the same behaviour when streaming to mutiple clients concurrently. This seems to eliminate the NAS hardware as the source of the problem.
Anyone got any insight into why my bandwidth would be so constrained with 2+ clients? Although there would be some contention which would reduce the utilisation, I wouldn't have thought it would reduce it by 85% adding a second client? Equally I imagined that streaming from a single file on disk like an MKV would be quite suitable for serving multiple clients, but maybe the format requires lots of intra-archive seeking which is adding latency? Unfortunately the tools on nas4free (BSD based) don't give me deep insight into what the hardware is doing. Streaming DVD images from MKV is fine, but obviously the demands are much less. Definitely feels like a bandwidth & latency issue somewhere, but where to look?
I'm having some grief with my home media server network and I thought I'd throw it out here to see if anyone can offer some insight.
Basically I've got a NAS with all my DVDs and BDs ripped into MKV format, and a number of media player devices attached to various screens around the house. Any one device can stream a BD film fine; start another stream concurrently and one of them will get choppy in playback. Start another stream and it's choppy all round.
The streamers are all Kodi boxes running OpenElec latest version - either Amazon Fire TV 4K players or self-build boxes built on Intel NUC. All are wired Gigabit Ethernet. Network switches (there are a few around the house) are medium end Cisco SG110-16 units that can support Gigabit ethernet on multiple channels concurrently (i.e. not cheapo units which have switching bandwidth issues). The NAS server I had running was a 1U Dell server with DAS in a Dell MD1000 disk array with 15x2Tb disks hardware RAID 5, running nas4free (BSD).
The NAS can sustain 85Mbps reading and writing across the network via e.g. Windows file copy of one of the MKV files (i.e. limited by the Gigabit network). Observing network utilisation when playing back the same file shows very peaky bandwidth usage about 5Mbps max for a BD image. Running a second streamer (when it gets choppy) shows network utilisation to about 9Mbps, running a third gets it to about 10Mbps.
I swapped out the NAS for something a bit lower end - an HP microserver with 4x4Tb disks software RAID with ZFS. This could sustain about 54Mbps for single file copy but showed the same behaviour when streaming to mutiple clients concurrently. This seems to eliminate the NAS hardware as the source of the problem.
Anyone got any insight into why my bandwidth would be so constrained with 2+ clients? Although there would be some contention which would reduce the utilisation, I wouldn't have thought it would reduce it by 85% adding a second client? Equally I imagined that streaming from a single file on disk like an MKV would be quite suitable for serving multiple clients, but maybe the format requires lots of intra-archive seeking which is adding latency? Unfortunately the tools on nas4free (BSD based) don't give me deep insight into what the hardware is doing. Streaming DVD images from MKV is fine, but obviously the demands are much less. Definitely feels like a bandwidth & latency issue somewhere, but where to look?
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