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The best filesystem for a mythtv data drive is usually said to be xfs,
because it handles large files well.

But primarily you should ensure that you align partitions properly.
Google 4k sectors. Use a recent version partitioning tool.

On Mon, Nov 11, 2013 at 11:43 PM, tortise <tortise@paradise.net.nz> wrote:
> Hi
> Using Mythbuntu 10.04 I have attached a HDD to backup recordings to (to
> create space...), a recent 3TB drive formatted ext4 gives a warning that the
> partition is misaligned by 3072 bytes. It seems healthy but is reported as
> largely full, however I am not convinced it is because a 12G file seemed to
> copy across still.
> I'm going to format another, and maybe see what copies across.
> The question I think I need to ask is what format should I use for the new
> 3T drive, however I am open to suggestions that I may not be asking the best
> question here!
> In anticipation many thanks!
>
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On 11/11/13 23:43, tortise wrote:
> Hi
> Using Mythbuntu 10.04 I have attached a HDD to backup recordings to
> (to create space...), a recent 3TB drive formatted ext4 gives a
> warning that the partition is misaligned by 3072 bytes. It seems
> healthy but is reported as largely full, however I am not convinced it
> is because a 12G file seemed to copy across still.
> I'm going to format another, and maybe see what copies across.
> The question I think I need to ask is what format should I use for the
> new 3T drive, however I am open to suggestions that I may not be
> asking the best question here!
> In anticipation many thanks!
Its not the filesystem, its the start and end locations of the
partition. Since you're offset by 3k on a disk with 4k sectors, to
read a 4k sector then it has to read 3k then 1k from the next block to
get a full block.

TO FIX IT:
So you need to run gparted to delete and recreate the partition, then
put a filesystem on it with mkfs.ext4.
This will lose all the data on the partition unless you copy it
elsewhere and back afterwards.

fdisk is not suitable because it makes the 4k alignment problems hard to
calculate.
This is a problem with all disks that use 4k blocks, more common on
large drives. Its not specifically related to any 2TB limit.

--
Criggie

http://criggie.org.nz/


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Hi
a question out of curiosity, not necessity. Is Disk Utility or gparted
capable of doing this natively? It's been a long time since I used these
applications, as I usually wobble my way along on the command line!


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On Tue, Nov 12, 2013 at 8:35 AM, Noel & Diane <noel@igrin.co.nz> wrote:
> Hi
> a question out of curiosity, not necessity. Is Disk Utility or gparted
> capable of doing this natively? It's been a long time since I used these
> applications, as I usually wobble my way along on the command line!
>
>

Do you mean the alignment issue? Depends which version, some care is needed.

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On 12/11/13 08:53, Nick Rout wrote:
> Do you mean the alignment issue? Depends which version, some care is needed.

There's a utility called gdisk, works much the same as fdisk but is smarter.

hads
--
http://nice.net.nz

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Do you mean the alignment issue? Depends which version, some care is needed.


Yes, I meant the alignment issue.
Disk Utility version 3.0.2
GParted version 0.11.0

On 12/11/13 08:53, Nick Rout wrote:
> Do you mean the alignment issue? Depends which version, some care is needed.

There's a utility called gdisk, works much the same as fdisk but is smarter.

hads


Oops... posted in HTML before, sorry 'bout that. :-o

gdisk is in beta? looks interesting.


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On 12/11/13 10:24, Noel & Diane wrote:
> gdisk is in beta? looks interesting.

Didn't know it was in beta, I've used it to partition several 3TB disks,
I did one yesterday actually. Seems to work fine.

hads
--
http://nice.net.nz

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On Tue, 12 Nov 2013 07:48:14 +1300, you wrote:

>The best filesystem for a mythtv data drive is usually said to be xfs,
>because it handles large files well.

Actually, that should be xfs or jfs. I have always used jfs and been
very pleased with the results. Lots of people use xfs, and the
current version of ext4 seems OK, but still is not recommended as far
as I can tell.

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On 12/11/13 13:50, Stephen Worthington wrote:
> Actually, that should be xfs or jfs. I have always used jfs and been
> very pleased with the results. Lots of people use xfs, and the
> current version of ext4 seems OK, but still is not recommended as far
> as I can tell.

I always used to use JFS which I had no issues with. These days I used
ext4 on everything with no problems.

hads
--
http://nice.net.nz

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You should remove the MBR DOS partition label and use GPT style partition
labels where possible as well. This has several benefits including 4k
alignment being pretty much automatic.


On 12 November 2013 13:59, Hadley Rich <hads@nice.net.nz> wrote:

> On 12/11/13 13:50, Stephen Worthington wrote:
>
>> Actually, that should be xfs or jfs. I have always used jfs and been
>> very pleased with the results. Lots of people use xfs, and the
>> current version of ext4 seems OK, but still is not recommended as far
>> as I can tell.
>>
>
> I always used to use JFS which I had no issues with. These days I used
> ext4 on everything with no problems.
>
> hads
> --
> http://nice.net.nz
>
>
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>

On 12/11/2013 8:19 a.m., criggie wrote:
> On 11/11/13 23:43, tortise wrote:
>
> TO FIX IT:
> So you need to run gparted to delete and recreate the partition then
> put a filesystem on it with mkfs.ext4.
> This will lose all the data on the partition unless you copy it
> elsewhere and back afterwards.

gparted on mythbuntu 12.04 (0.11.0) has done the trick - when selecting
the partition the 2nd trick is to select "advanced", then "gpt",
thereafter its intuitive. (Mythbuntu 10.04 has one version too old of
gparted it seems, maybe it can be updated, I just used the 12.04 box)

Much obliged (again) thanks gurus.


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On 12/11/2013 6:30 p.m., tortise wrote:
> On 12/11/2013 8:19 a.m., criggie wrote:
>> On 11/11/13 23:43, tortise wrote:
>>
>> TO FIX IT:
>> So you need to run gparted to delete and recreate the partition then
>> put a filesystem on it with mkfs.ext4.
>> This will lose all the data on the partition unless you copy it
>> elsewhere and back afterwards.
>
> gparted on mythbuntu 12.04 (0.11.0) has done the trick - when selecting
> the partition the 2nd trick is to select "advanced", then "gpt",
> thereafter its intuitive. (Mythbuntu 10.04 has one version too old of
> gparted it seems, maybe it can be updated, I just used the 12.04 box)

Formatted a new 3TB drive, cp all files across, to get:
@mythtv0:~$ df
Filesystem 1K-blocks Used Available Use% Mounted on
....
/dev/sde1 2884285068 2791119844 0 100% /media/3TB#2
/dev/sdf1 2884283608 2832514960 0 100% /media/3TB#2a

The new drive has the suffix "a".

Not sure it makes a lot of difference beyond removing an error message?!


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On Wed, Nov 13, 2013 at 8:02 PM, tortise <tortise@paradise.net.nz> wrote:
> On 12/11/2013 6:30 p.m., tortise wrote:
>>
>> On 12/11/2013 8:19 a.m., criggie wrote:
>>>
>>> On 11/11/13 23:43, tortise wrote:
>>>
>>> TO FIX IT:
>>> So you need to run gparted to delete and recreate the partition then
>>> put a filesystem on it with mkfs.ext4.
>>> This will lose all the data on the partition unless you copy it
>>> elsewhere and back afterwards.
>>
>>
>> gparted on mythbuntu 12.04 (0.11.0) has done the trick - when selecting
>> the partition the 2nd trick is to select "advanced", then "gpt",
>> thereafter its intuitive. (Mythbuntu 10.04 has one version too old of
>> gparted it seems, maybe it can be updated, I just used the 12.04 box)
>
>
> Formatted a new 3TB drive, cp all files across, to get:
> @mythtv0:~$ df
> Filesystem 1K-blocks Used Available Use% Mounted on
> ....
> /dev/sde1 2884285068 2791119844 0 100% /media/3TB#2
> /dev/sdf1 2884283608 2832514960 0 100% /media/3TB#2a
>
> The new drive has the suffix "a".
>
> Not sure it makes a lot of difference beyond removing an error message?!
>

What difference were you looking to find.

Drives with 4k sectors with misaligned partitions perform badly, but
they still hold the same amount of data.

>
>
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