[mythtvnz] Myth & Raid. SW or HW..

[noel at igrin.co.nz]

snip..
> The key issue with RAID for mythtv is fragmentation, fragmentation can
> offset the increased perofmance you get from having raid.
> The file I/O profile of a mythtv setup is quite different from what RAID
> was designed and optimized for.
>

My own experience of to raid or not to raid..
I have software raid 1 for my system drive, and a raid 5 array for my
storage (not using storage groups and the drives run via a $50 fake-raid
card bought off TradeMe - I bought 2, so I could have one as a spare) on a
dedicated back end, and watch TV via an old ex-lease compaq.  We often
have 6 recordings happening simultaneously plus watching something else.
We can't detect any performance issues & the system has been up for YEARS
(save for some power cuts).
Having suffered dive failure from buying cheap second hand **GASP** drives
in the early days (OK I admit it was more than one drive, my own fault I
know), I simply changed the drive & away we went within half an hour -
hasd to fight my way in to where the server was bueried.  no fuss no
fiddle with a simple hot-swap. The **NEW** drive is larger than the
remaining array drives, so I have wasted a bit of space etc on that
drive.. but hey, at the end of the day our music vids & all the kid's
programmes are still there & I don't need to shuffle through a 100 or so
DVDs to find what I want to watch.
With fragmentation, I think it's mind over matter, if you don't mind, then
it doesn't matter - as long as I can't TELL it's there!
I will eventually up-size the remainder of the drives but that won't
happen till there is another failure.