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

[Stephen Villano]

My primary BE is an old Dell Poweredge 2850, hanging on gigabit. Never
had congestion or pauses with the RAID5 or even with additional
storage via NFS links over gigabit.
Of course, that's a dual Xeon processor.

On 6/2/15, Jason But <jbut at swin.edu.au> wrote:
>
>>> Therealways seems to be people querying recording rates, yet I have never
>>> seen problems. My current install has Myth running on the same physical
>>> box as my 6-disk RAID-5 array and I have never seen any problems with up
>>> to 7 concurrent recordings, two concurrent playbacks, while the same box
>>> is also my home network gateway, file server, DNS server, print server,
>>> everything else server. While the computer is an i5 and not a cheap NAS,
>>> the disks are surely not going to be a problem...
>>>
>>> Jason
>>>
>>>
>>> --
>>>
>>> ----------
>> I understood the query to relate to network I/O. Having your disk on the
>> same machine as the backend will result in completely different writing
>> and buffering characteristics compared with an NFS mount which, for
>> example may not have any buffering and may just drop packets during
>> transient congestion spikes. As I understand it at least.
>>
>> In your situation I would expect substantial stuttering of the playback
>> before the loss of any recording information. Recording to a NFS mount
>> might result in recording loss before playback stuttering is even
>> visible.
> I agree, however as previously mentioned, a gigabit network can easily cope
>
> with digital video bit rates which arenot high, perhaps an NFS mount may be
>
> an issue for 3 or 4 concurrent recordings/playbacks but it should cope with
>
> most scenarios. Also, given that networks nowadays are typically switched,
> as long as there is no router with queuing in the path, you should not see
> much delay variation to impact playback and recording. I think the main
> impact is more likely to be the CPU performance of the (typically ARM)
> processor on the NAS, unless you are overloading the NAS with work to do, I
>
> would expect it to survive a simple/low recording/playback environment
>
> I think the same applies when people suggest putting the DB on another
> spindle. I have not bothered to do so, and as I stated, my box performs many
>
> tasks and has never skipped a beat even with a half dozen recordings and two
>
> playbacks
>
>
>
>
>
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