[mythtv-users] WD15EARS WD Green drives

[Larry Finger]

On 05/08/2011 11:20 PM, Nick Rout wrote:
> On Mon, May 9, 2011 at 2:29 PM, David Whyte<david.whyte at gmail.com>  wrote:
>> On Mon, Mar 14, 2011 at 2:10 PM, Kevin Ross<kevin at familyross.net>  wrote:
>>> On 3/13/2011 8:29 PM, Digital Hit Entertainment wrote:
>>>> Found a great sale on the WD15EARS Green 1.5 TB drive. I saw some earlier stuff on the list about the drive and wanted to know if the latest MythTV versions have any problems with them.
>>>>
>>>> Any tips or things to watch out for?
>>>>
>>>> Thanks.
>>>
>>> Those drives have 4K sectors, so just make sure you start your
>>> partitions on an even multiple of 8 sectors (the drive lies to the OS
>>> and reports that it has 512-byte sectors.  4096/512 is 8), and you're
>>> good to go.  If you don't, performance will suck.
>>
>>
>> Doh!
>>
>> So I bought one of these about 12 months ago and use it as my primary
>> recording drive in my BE (which at the time was on mythbuntu 9.10).
>> Just lately, I have noticed some terrible issues which I believe to be
>> performance related.  Last night, I was playing back (on a remote FE)
>> a HD recording that was still in progress and another SD recording was
>> also being recorded and got kicked out of playback and noted that my
>> commercial flagging jobs seemed to have terminate prematurely.  I was
>> also experiencing choppiness as recordings were being expired by the
>> BE, something that has started to happen in the last couple of months.
>>   WD forums seem to indicate that drive performance degrades as the
>> disk get greater than 75% full, which I guess has happened in the last
>> couple of months.  When I checked the output of hdparms for the disk,
>> my single XFS partition starts at sector 63!  Doh!
>>
>> I understand that newer versions of mythbuntu (greater than or equal
>> to 10.04, which I am currently running) handle the larger sectors
>> sizes much more gracefully.
>>
>> Quick question, can anything be done?  Now it is full of recordings, I
>> don't want to go and re-partition it and erase all of my data.  I am
>> guessing I need to go and buy a second disk and copy all my data to
>> that and then repartition the original. :(
>
> yes, but enjoy the extra space, you can never have too much of it!

The problem is very simple when you have only one partition. Even if fdisk, or 
whatever tool you use does not support 4K sectors, just make sure partition 1 
starts at sector 64, not 63. I have a drive with 4K sectors that had an openSUSE 
11.1 release and multiple partitions. I did it by trial and error by creating a 
partition with the desired number of GB, then noting the ending sector, deleting 
the proposed partition, and then re-add it by sector with the last one at 8N-1. 
With 8 partitions, it was a pain, but it works.