[mythtv-users] Does MythDora-12 support advanced format drives?

Sun Jun 20 20:46:19 UTC 2010

Jarod Wilson wrote:
> On Sat, Jun 19, 2010 at 9:03 AM, Don Brett <dlbrett at zoominternet.net> wrote:
>   
>> Jarod Wilson wrote:
>>     
>>> On Fri, Jun 18, 2010 at 8:27 PM, Don Brett <dlbrett at zoominternet.net>
>>> wrote:
>>>
>>>       
>>>> I built a brand new MythDora box with a Western Digital 1TB drive (model
>>>> WD10EARS).  It uses advanced formating (4k physical sectors), but now I'm
>>>> not so sure it's supported yet in Fedora.  Does anyone know if it is...or
>>>> if
>>>> not, any suggestions?
>>>>
>>>> Here's a couple of threads I came across (they imply it's not supported
>>>> until Fedora-13):
>>>>
>>>> http://fedoraforum.org/forum/showthread.php?t=240404&highlight=WD10EARS
>>>> http://thread.gmane.org/gmane.linux.utilities.util-linux-ng/2926
>>>>
>>>>         
>>> Thread says 2.6.31+ and either a new enough util-linux-ng or parted
>>> are sufficient. Fedora 12 is fine on the kernel side, not certain on
>>> the userspace side. It *can* be done w/older parted, but requires a
>>> bit of manual work partitioning the drive to make sure you get proper
>>> alignment. Anaconda may do that for you already anyway, but I'm not
>>> sure. Newer parted has a -a/--align flag that definitely gets it
>>> right, and is definitely available in Fedora 13. Even an updated build
>>> being available for F12 wouldn't help though if it is indeed required
>>> for Anaconda to get things right, since its the parted built into the
>>> installer image that Anaconda uses. So all that to say... It might
>>> work, it might not. :)
>>>
>>> A thought though... Start up an F13 installer. Partition the disk as
>>> you want to use it w/MythDora. Restart the machine and boot the
>>> MythDora 12 installer. Instead of repartitioning, use the existing
>>> partitions, which should all be properly aligned. Proceed w/the rest
>>> of the install as normal.
>>>
>>>
>>>       
>> That sounded like a great idea, so I gave it a try, but got stuck.  I used
>> the live-cd version of f-13 and selected the "install to hard disk" icon
>> after it loaded.  The installation did everything very automatically.  It
>> actually did the entire install before I caught it, so I had to start over
>> and hit the reset button immediately after the formats finished.  The format
>> looked very similar to the md-12 format.  It did the same motions and took
>> about the same time...I think it did the same thing as md-12.
>>
>> I got the partitioning and formatting done with Fedora-13, went back to
>> md-12 and walked through the standard installation steps, but there was no
>> selection to use the existing partitioning; I tried every combination.  I
>> would have sworn I had seen that selection some time ago.
>>     
>
> Hrm, yeah, I swear there *is* a way to do custom partitioning, but its
> been a while since I've stepped through the MD12 installer.
>
>   
>> By the way, I don't know that this installation is actually bad.  MD-12
>> install and runs fine, but has a weird slow-down (about 50% of the time).
>>  When it's fast, it's pretty fast...when it's slowed-down, it's really slow.
>>  It's a lot like the other threads were describing.
>>
>> The first time I installed md-12 on this machine, it warned me that there
>> was something wrong with the disk and offered to fix it, which I let it do.
>>  I just assumed it had something to do with the advanced formatting feature.
>>  The installation went fine after that.  I later noticed the lags and
>> started looking into it.  Is there a way to tell if it's right?
>>     
>
> I'm sure there is, but I'm afraid I don't know what it is offhand.
>
>   

I found this information about the format alignment.  If the drive is 
properly set up, the starting point for the first partition is shifted 
by 1 (but I'm not sure it's this simple).  It looks like:
( http://www.linuxconfig.org/linux-wd-ears-advanced-format )

.............
Partition table for WD EARS hard drive starting with sector 63

# fdisk -lu /dev/sda

Disk /dev/sda: 1000.2 GB, 1000204886016 bytes
255 heads, 63 sectors/track, 121601 cylinders, total 1953525168 sectors
Units = sectors of 1 * 512 = 512 bytes
Disk identifier: 0x10bd10bc

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1              63    20971583    10485760+  83  Linux

.....................

Partition table for WD EARS hard drive starting with sector 64:

# fdisk -lu /dev/sda

Disk /dev/sda: 1000.2 GB, 1000204886016 bytes
255 heads, 63 sectors/track, 121601 cylinders, total 1953525168 sectors
Units = sectors of 1 * 512 = 512 bytes
Disk identifier: 0x10bd10bc

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1              64    16777280     8388608+  83  Linux

...........................

I reinstalled with MD-12 and checked it; it was set to 63, so I assume 
that if mine is not right.  I don't really see a simple way to manually 
partition, format, and re-install Mythdora-12.  I'm considering buying 
another drive with regular sector sizing just to get this box working.  
I'll keep this drive until advanced formatting becomes a little more 
mainstream (Fedora-13).

A little off-topic....while google-ing I also came across this; the 
factory spin-down timer on the green drive is set to 8 seconds, but 
nobody seems to like that number.  Here's a command to change it (but 
the man pages tag it as "very dangerous").

(http://www.silentpcreview.com/forums/viewtopic.php?p=498971&sid=d83ce15578282f9fca5e737db5b02fb5)

hdparm -S 242 /dev/sda
which sets the spindown timeout to 1 hour

Now:
smartctl -a -d ata /dev/sda
shows Load_Cycle_Count stopped at 435228