[mythtv-users] Wiki: Balanced Disk I/O

Peter Bennett (cats22) cats22 at comcast.net
Tue Aug 11 19:57:58 UTC 2015


On 08/11/2015 01:44 PM, Michael T. Dean wrote:
>
> a) it creates files with the least amount of fragmentation (this is
> the primary benefit)***
A good point I had not thought of.

> b) when hard drives fill up, it doesn't favor a single hard drive for
> every single recording, leading to all new recordings going to the
> same drive and all expired recordings coming from that same drive
> (meaning that before long, the system is expiring new recordings when
> there are tons of older--possibly Deleted and/or Watched--recordings
> that could be expired instead if the system would just choose another
> disk).  If using Balanced Free Space or Balanced Percent Free Space,
> this is exactly what happens when disks fill up and autoexpire kicks
> in.  See
> http://www.gossamer-threads.com/lists/mythtv/users/556505#556505
> (note, too, that neither Combination, nor Balanced Disk I/O will avert
> this issue if the user never records multiple shows at the same
> time--in which case, the user /must/ rebalance his/her recordings)****.

This is I assume when you set "Deleted Max Age" to -1 so that it keeps
all of your files around for as long as possible (or set auto-expire in
your recording settings and never delete anything). I gave up on this
after I got burned when the expiring of old files did not keep up with
recording of new ones and recordings failed because of running out of
disk space. It seems to me that this is not the best idea, having your
disk always at 99% full will, I think, cause fragmentation. So now I set
it to 7 so that deleted recordings are removed after 7 days. Another
problem with setting "Deleted Max Age" to -1 is that it is difficult to
know how much space you have available for recordings since your disk is
always 99% full.

Regarding re-balancing your storage groups and using Archive storage
groups, doing this requires some technical finesse to find the file
names of your recordings and move them around. This is not the easiest
thing for a newcomer. I can certainly document how and why to do it for
those wanting to get into it.

Thanks for all the information, I will digest it and try to explain it
in the wiki.

Peter
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mythtv.org/pipermail/mythtv-users/attachments/20150811/8e0671f1/attachment-0001.html>


More information about the mythtv-users mailing list