[mythtv] Problems with using LVM for large storage

[Mario Limonciello]

Ed Wildgoose wrote:

> Neale Swinnerton wrote:
>
>> Why is this a surprise? You have one logical drive composed of multiple
>> physical drives and a bit of it fails. This would be the same if you had
>> one physical drive.
>>
>> Why not use RAID-{1|5} drives as the PV's in your LVM volume group ?
>>  
>>
>
> Storage space drops...  You now need up to twice as many disks basically
>
> Consider having three disks mounted as /store1, /store2 and /store3. 
> Now you can take down any one of them and the other two are still
> accessible.
> With Raid0 though you lose the whole array.  There is sometimes
> another mode called JBOD which can sometimes work where a failed disk
> just looses you some (parts) of the files, but I have never tried this...
>
> I can see some definite merits in the idea of having multiple store
> locations, even if the record location is fixed and you have to
> shuffle them around later.
>
> I just bought a new 400Gb drive to replace the 300Gb on in my current
> machine.  There is 1Tb on another fileserver in RAID5.  One thing
> which becomes apparent with this amount of storage is that it's quite
> hard to shuffle things around later and upgrade the odd disk here and
> there...  It's very easy to sit there and say make it Raid 1/5, but
> the cost, heat, power noise and size requirements are considerable -
> not to mention the hassle when you need to upgrade
>
> Ed W
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I do like the idea of being able to span across drives via several
different mounts.  This also brings up the possiblity of spanning
accross several different NFS mounts as well then too, not just sticking
to one NFS server.  I will be setting up LVM at the end of this summer
when I pick up a few more drives. If that can be avoided by a script
like this, i'd prefer this route.