[mythtv-users] OT: Hybrid drives in a RAID?

Simon Hobson linux at thehobsons.co.uk
Wed Aug 20 15:27:03 UTC 2014


Gary Buhrmaster <gary.buhrmaster at gmail.com> wrote:

> Multi-drive vibrations can be a significant source of soft errors
> on drives.

I recall watching a video some time ago where someone setup some very fine grained monitoring on an array of drives - and then SHOUTED at the array. The monitoring was able to detect very small fluctuations in latency (IIRC) due to the shouting.

> <conjecture>
> Since I have not actually run tests to provide statistically
> significant measurements, it is my guess that SSHDs,
> used only for recording/playback drives, are not likely to
> see the 70% performance improvements, since an 8GB
> cache is no where near large enough to contain your
> content library, which is mostly streamed sequentially.
> There may be a small improvement in (filesystem)
> metadata access.
> </conjecture>

I concur.
It's likely to be helpful for the OS & database, but since we shouldn't have those on the same drive as the recordings, there'e little to gain. As pointed out, unless you are in the habit of watching a small number of recordings over and over (got young kids in the family ?) then the only thing that might reasonable benefit from the SSD cache is the filesystem metadata. In the grand scheme of things, I doubt if the difference in performance from that would be worth the price premium.



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