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

[Gary Buhrmaster]

On Mon, Jun 1, 2015 at 3:08 PM, Tom Hayward <esarfl at gmail.com> wrote:
> .... If 8 programs are
> recording, it will need to seek to 8 different disk positions per
> second

Depending on the specific file system type, it can actually
be more than that, since the metadata also needs to be
updated, which may require other metadata to be updated.....
Whether those are forced to be synchronous (or can be
bundled to mitigate against the seek penalty) or not will
also depend on the file system type and settings such as
barriers.  Many of the consumer NAS devices do not let
one have full control over some of these capabilities.

And there are many possible configurations of most NAS
devices (i.e. raid topologies), some of which may also
require many reads to satisfy the write.

And while recording is not usually disk intensive, your
particular environment will vary.  As per the previous poster,
test, test, test, and then test (with at least twice the load
you expect to ever encounter, and ideally a much larger
multiplier since I/O is not constant, but bursty).  Once
you know the maximum you can run with, you will be
able to make a more informed decision regarding how
close to the maximum you wish to live.