[mythtv-users] Storage Groups - Disks often get over used when others have free space

[Michael T. Dean]

On 05/13/2009 06:44 AM, David Whyte wrote:
> On Wed, May 13, 2009 at 7:45 PM, David Whyte wrote:
>   
>> Hi all,
>>
>> I have three disks in in my default storage group, which is the only one I have.
>>
>> For some reason, it is common for myth to record to one of those disks
>> despite there not being enough space for the whole show and although
>> there is space on the other two disks.
>>
>> For example, there was 549MB left on disk 1 this morning, yet tonight,
>> myth started recording a 45 minute SD show and it ran out after about
>> 15 mins.  Not good :(  There were other recordings occurring at the
>> same time.  I also do have the storage group setup to save 7GB of free
>> space, but that doesn't seem to help.
> I have been looking at my setup.  I have now removed all of the
> symlinks from the drive that used to be the primary drive so maybe we
> will see some improvement soon.
>
> The source of the problem seems to be though that myth will still
> record to a drive in the storage group even when the minimum space
> threshold has been exceeded.  There are about 30GBs of recordings that
> can be expired from the deleted group, but they are all on the one
> disk it seems.
>
> Is there any way to prevent myth from selecting a disk that is below
> the threshold as a storage device?

No.  Myth's storage groups are designed to balance I/O load, not to 
select the filesystem whose recordings are highest-priority to expire 
(i.e. LiveTV, then Deleted, then auto-expirable normal recordings).

>   Alternatively, I need a cron
> script that runs every x minutes to move recordings from a full disk
> to a disk that has expirable recordings on it.
>   

That works.  You can use the myth_archive_job.pl script to do it.  It's 
not set up to use storage groups, so you'll have to "hard-code" the list 
of directories and free-space information at the top.  The only thing 
I'd change is removing the "ln -s" stuff from the $cmd (I think it's 
line 122).

Mike