[mythtv-users] Suggestions for a partition structure

[Eric Sharkey]

On Mon, Oct 21, 2013 at 8:30 PM, R. G. Newbury <newbury at mandamus.org> wrote:
> 2 aspects are involved. The usual chunk of space allocated on a hard drive
> is 4 or 8k. xfs lets you allocate large contiguous chunks of disk space
> which reduces head movement.

Not really.  Just because the block size is 4K doesn't mean more space
won't be allocated in a contiguous run.  ext4 doesn't fragment so
badly that every block is its own fragment.

> Secondly, xfs is really fast at deleting files.
> ext4 is way slow at deleting large files.

And this affects "actual perceived performance" to the mythtv user how?

>> My approach is to have the absolute minimum number of partitions.  I
>> usually just have /, /boot (tiny), and swap.  I would get an SSD and
>> set these up on there,
>
>
> THAT is a recipe for disaster. If you have one process go run-away and
> spam-fill your /var/log/messages or /var/lib/mysql logging folders you will
> NOT be able to recover.

Meh.  It's a trade off thing.  Do you want to deal with a wrong
upfront partition allocation or the problems that happen when the
whole disk fills?  Partitions don't solve this problem completely.
Any drive may run out of space if not monitored.  Compartmentalizing
it seems to exacerbate this problem in my experience.  (And I've been
doing Unix administration stuff for 18 years.)

Some people are really fixated on having lots of partitions.  I've
never understood that.  It seems to be worse among people who run
distributions that don't upgrade in place well.

> You don't actually need to set up a 'storage group' a-la-a LVM. Myth will be
> quite happy to use them as mount points, and balance the usage.

Multiple folders in different filesystems that MythTV balances usage
across *is* a storage group.

http://www.mythtv.org/wiki/Storage_Groups

And you don't want to use the mount-point of a filesystem as the root
of a storage group entry.  You should always use a folder within the
filesystem.

Eric