[mythtv-users] MythTV and LVM
roland at astrofoto.org
Tue Jan 31 17:24:13 UTC 2006
>>>>> "PAUL" == PAUL WILLIAMSON <pwilliamson at mandtbank.com> writes:
>>>> thehappyfunball at gmail.com 01/31/06 9:30 AM >>>
>> I have two quick questions about setting up MythTV to store its
>> data on an LVM array.
>> - After a certain amount of time, can I set individual drives
>> to spin down when the data on that particular drive isn't
>> being accessed? (If I have shows on a hard disk in the
>> array that aren't being watched in a couple of days, I
>> would like for that drive to go offline for a while.)
PAUL> I'm not sure what the motivator here is, but I haven't figure
PAUL> out a way to spin down a drive in an LVM array. Powering down
PAUL> an entire PC for a month saved me a grand total of ~4 USD. I
PAUL> would suspect powering down 1 drive might save you 3 dollars
PAUL> over the course of a year.
As someone else pointed out, I'd be more concerned about the
wear-and-tear on the drives. Many drives seem to fail more frequently
at start-up, or maybe that's just when they show the problem.
Unless the drive is off a large fraction of the time, it seems unlikely
to help. And it would have to be a drive not in use for anything
else.... Probably not worth the trouble.
>> Are there any other concerns for using LVM? Are there any
>> serious speed penalties?
PAUL> Yes, you are putting yourself in peril. The more drives you
PAUL> add to an LVM array, the more likely you are to have total
PAUL> filesystem failure. If one of the drives dies, your whole LVM
PAUL> array is pretty much done for.
Unless you LVM on top of RAID-1 which is what I do. While this is
somewhat wasteful if you put a low value on your TV recordings, I have
other data which I do value and they share the LVM on RAID-1 disks in
different partitions. Being able to expand the space for my photography
work at the expense of my TV space is useful to me....
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Roland B. Roberts, PhD RL Enterprises
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roland at astrofoto.org Brooklyn, NY 11220
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