[mythtv-users] LVM RAID 5 partition schemes

Dan Christensen jdc at uwo.ca
Thu Apr 7 02:26:27 UTC 2005


David <myth at dgreaves.com> writes:

> Milan Andric wrote:
>
>>there's a problem with that.
>>1) no wired network to bedroom, just wireless 802.11B 5-8Mb/s?
>
> mmm - if that speed is reliable then it's fine - but if you end up with 
> the connection dropping with an nfs mount trying to write then my 
> experience is that ivtv goes AWOL. I'd avoid a wireless connection 
> unless you feel it's as stable as wire.

I found that 802.11b was not quite able to keep up with PVR-350
encoded material, but 802.11g can handle at least two streams at the
same time.

>>>But you'll have no redundancy until you buy the 3rd drive.
>>>You also can't 'add drives as time goes by' to a raid 5.
>>>
>>unless i use the 'missing' trick?
>>
> nope.
> The only way to add drives is an unsupported program called raidreconf 

The web page for raidreconf

  http://unthought.net/raidreconf/

says it has a current maintainer, and say no bugs are known, so maybe
this program shouldn't be discounted completely.  I plan to use it
when I add a fourth drive to my RAID-5 array, so if anyone has any
more information about it, I'd like to hear it.  It's also mentioned
in the Software RAID Howto:

  http://www.tldp.org/HOWTO/Software-RAID-HOWTO-10.html#ss10.1

Maybe this program should be mentioned on

  http://www.mythtv.info/moin.cgi/AdministrationSoftware_2fLvmRaid

> Sean's idea of lots of mini-raid5'ed partitions is very interesting 
> though. I haven't thought it through. I think you could do it just using 
> the lvm 'move blocks' approach (ie without needing to repeatedly 
> shrink/grow the filesystem - just one growfs at the end).
> I'd rate it as lvm/md experts only (which isn't that hard TBH)

Hmm, I don't see any posts by anyone named Sean in this thread.
What idea did he suggest?

Dan


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