[mythtv-users] Storing recordings on a NAS via NFS (I/O concerns)

Mon Jun 1 16:03:09 UTC 2015

On 01 Jun 2015, at 02:53, Phill Edwards <philledwards at gmail.com> wrote:

> My current setup is a virtualised (ESXi) MythBuntu which uses an NFS share provided by another Ubuntu VM on the same ESXi hypervisor. I have 2 x PCI DVB-T tuners passed through to the MythBuntu VM plus an HD Homerun which means I can record up to 8 programs at once (I set the max per channel to 2). I was originally worried that this would suffer from disk I/O problems but it seems to work fine.
> 
> I'm now thinking of ditching the NFS VM and using my QNAP TS-410 NAS to provide the NFS share. But I'm worried that this may suffer from I/O bottlenecks. As an example, I copied a 800MB file from the NFS VM to the MythBuntu VM and it took 14 seconds. But when I copied the same file from MythBuntu VM to the NAS it took 49 seconds.
800MB : 49sec = 130Mb/s
Divided by 8 = 16Mb/s
You can check your average needed bitrate from recordings you already have. 
> 
> The NAS has a gigabit ethernet port but it's a few years old, and the disks are Hitachi 7200 RPM. Do you think it will be up to the job? Is there a test I could do to check before I head down this path?
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