[mythtv-users] Single WD GP disk fast enough for live 720p?

[John Drescher]

On Wed, Dec 2, 2009 at 12:45 AM, Jon Whitear <jon at whitear.org> wrote:
>
>> >
>> > Please excuse my ignorance here (relatively new to RAID etc.) but
>> what's not
>> > to support?
>> > Surely the OS just sees the drive as a lump of blocks and allocates
>> > accordingly?
>> >
>> > Also, I have two of the 1TB in a mirrored software RAID and they are
>> working
>> > great.  Wonder what went wrong with the 1.5TB versions.
>> >
>>
>> The problem is if the heads are automatically parked and the raid is
>> called on the software raid may assume the drive is bad if it takes
>> too long to recover from the parked heads and kick the drive out of
>> the array.
>>
>
> With the WD drives, it seems there are a couple of issues that have caused problems for RAID users. One is the head-park count(aka load cycle) rapidly increasing - IIRC the drives have a rated life of 300,000 load cycles, and people were seeing it increase at a rate of many hundreds per day, leading to an expected life of <3 years. Not much good, but not actually a performance issue.
>

I forgot about that. I can see that causing serious problems in server raids.

John