[mythtv-users] Recording and Archive Storage Approaches

[Joel Turner]

I appreciate all of the comments.  It's nice to know that I'm not out  
in left field on this.

On another note, I've been experimenting with H.264 encoding as a way  
to preserve HD content and conserve space.  My initial tests are not  
very promising.  The encoding times are horrendous. I've been  
converting MPEG content for several years now and x264 encoding is  
about an 11:1 time ratio for encoding one minute of 1080i content to  
720p on my old XP based P4 2.66mhz.  I've had the same results with  
Nero Recode.  I thought that perhaps my Mac, a dual G5 2.5 with 6GB  
of ram would be better, but the encoding times are still awful using  
Quicktime.  I'll probably post something here when I can actually get  
some repeatable results.
On Jul 10, 2006, at 11:04 PM, Steve Christall wrote:

> Some Raid5 comments for Joel
>
>
> I have been using RAID5 in Linux for four years.  There are three  
> kinds
> of RAID5 that I have come across.
>
> 1 / Real RAID5, where the parity information is generated on the card.
> You can boot from this (3ware, LSILogic, other server raid chipsets)
>
> 2 / Fake RAID5, where the parity information is generated by the CPU.
> The card has bios extensions so you can boot from it (apparently,  
> never
> tried) (Promise, Highpoint etc).  Driver is generally proprietary.
>
> 3 / Software RAID5, parity is generated by the CPU, you def can't boot
> from it.  Raid code is in the Linux kernel.
>
> At work I have used a lot of real RAID5, generally in Dell servers.
> Works well, is fast, monitoring is OK
>
> At home I started trying to use fake raid, because I couldn't afford /
> justify $1000 for a real raid card.  A lot of the proprietary drivers
> are locked to a particular kernel version, so upgrading is a  
> nightmare.
>   Sometimes you have to recreated the array, just to upgrade.
> Monitoring is, well, please stay clear
>
> Now I am using mdadm, to control true software RAID5 in Linux.  It is
> fast (Myth is ideal for RAID5, large sequential writes, hence you can
> have a large block size), mdadm has great monitoring, and you can
> upgrade your kernel without issues.  Can't boot from it (I use 2x80GB
> RAID1), which give me space for mythburn etc.
>
> I am using a fake raid card, highpoint 404, as my four channel ATA
> controller (but using the Linux simple ata driver for it).
>
> There is one thing to watch out for with software RAID5.  It doesn't
> like power outages.  It is very good at scrambling the superblock  
> on one
> or more drives if a power outage occurs on write.  You can recover,  
> but
> it is not pretty, and leaves you wondering where there is inconsistent
> data on the array.  I would recommend an UPS, and auto shutdown.
>
> HTHs
> Steve
>
>
>
>
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