[vdr] Re: Default video dir

[Emil Naepflein <Emil.Naepflein@philosys.de>]

On Sun, 16 Jan 2005 13:57:05 +0100, Beppe wrote:

> >One broken LVM volume will kill all recordings.
> >
> Are you sure?
> 
> AFAIHR it depends on what mod you use linear/striped and filesystem.

LVM combines partitions with any kind of fault-tolarance into one big
volume. Even if you combine only RAID5 partitions it can happen that you
loose data of the whole volume. Nothing is totally failure proof. A
friend of mine lost his data on a RAID5 because of a data corruption in
the controller. Or because of some event more than one disk in a RAID5
fails at the same time. If one of the components in a LVM fails then the
whole LVM volume is unusable. 

And if the big filesystem on the LVM volume get's corrupted by any means
then you may loose all your data. This is one of the reason why I have
distributed the data on multiple RAID5 partitions and use software RAID
instead of the hardware RAID functionality in the SX6000. I also have
put the recordings archive on different partitions where there is no
write activity. The day to day recordings go on to other partitions.
Only cutted recordings are moved to the archive. The house-keeping is
done about once a week and takes only a few minutes.

This all is no real problem if you have a backup. But you just cannot do
a backup for an acceptable price for this much data. So the only way to
go is to organize the data in a way so that the probability to loose
data by a single failure is very low. In the beginning I had several
catastrophic data losses and I learned my lession from them.

The file links of VDR allows to hide all this from the enduser very
easily. He just sees the the structure with the new recordings and the
genre folders with the archived recordings.

Cheers,
Emil