[mythtv-users] Yet another question about data storage

[Matt White]

On 2010-Nov-05 6:43 AM, Greg Oliver wrote:
> On 11/24/2010 04:41 AM, Johan wrote:
>> I need to create some (>1.5 TB) extra space for storing my DVD colection.
>> I store the majority of those in .mkv or .iso format. (turned
>> out the best way to retain menu's, subtitles and all AC3 streams)
>>
>> What is considered the best solution, from a Mythtv perspective?
>> Add a lot of storage to the backend, using either USB, SATA or eSATA?
>> (very cheap)
>> Add a NAS to the setup for storage of all data, except the DB?
>>
>> The backend motherboard supports hardware RAID.
[snip]
>
> I use an external HW raid enclosure attached via esata to my master
> backend. The next array I spend I will definitely spend the extra $150
> and get a unit with a configurable stripe size. This one is set at an
> unconfigurable 256k. While all of my media and virtual machine volume
> groups are configured with 4MB inode spacing, it could be quite a bit
> faster if I could tweak the array settings as well. This unit also only
> allows (1) array to be configured.

I tend to avoid hardware RAID for "casual" storage systems, and rely 
instead on linux software RAID (mdadm).  The problem with many consumer 
hardware RAID systems is that if you lose that piece of hardware, your 
RAID is useless until you replace it...

With most modern systems, the percentage of CPU power required for doing 
software RAID is minimal compared to what is available.  If your system 
dies, just plug the drives into something else, and there's your RAID. 
I've taken a 4-disk RAID5 array from a machine that died and plugged it 
into a spare workstation - 2 disks on internal SATA ports, and 2 using 
external USB<->SATA, and the raid assembled and was accessible normally 
(slower, of course, but I just needed to grab a couple of pieces of data 
from it).

I'm not saying hardware RAID doesn't have its place - I have a couple of 
hardware RAID systems at work and they're fantastic, but they have 
redundant paths, controllers, battery backup, etc.  Not something I can 
afford to have at home...

-- 
Matt White
whitem at arts.usask.ca
University of Saskatchewan