[mythtv-users] Options for Backing up Myth data

Another Sillyname anothersname at googlemail.com
Thu Dec 9 19:20:39 UTC 2010


On 9 December 2010 17:04, Brian Wood <beww at beww.org> wrote:
> On Thursday, December 09, 2010 09:43:45 am Raymond Wagner wrote:
>> On 12/9/2010 11:27, Brian Wood wrote:
>> > On Thursday, December 09, 2010 09:16:59 am Raymond Wagner wrote:
>> >> On 12/9/2010 10:03, Brian Wood wrote:
>> >>> On Wednesday, December 08, 2010 08:56:35 pm Raymond Wagner wrote:
>> >>>> On 12/8/2010 22:30, Brian Wood wrote:
>> >>>>> On Wednesday, December 08, 2010 06:07:20 pm Dave Badia wrote:
>> >>>>> Or folks are using some other option
>> >>>>
>> >>>> Flash drives are simply more convenient, and while smaller than
>> >>>> BD-Rs, still offer plenty of space for most people. The fact
>> >>>> that they are read/writable on just about any computer also
>> >>>> makes them far more useful.
>> >>>
>> >>> Flash drives are OK for documents and photos, but they are pretty
>> >>> much useless for any significant amount of video, especially HD.
>> >>> The amount of data you can store on a flash drive is about what
>> >>> is practical to store online.
>> >>
>> >> To be fair, bulk storage of HD video isn't something 'normal'
>> >> people generally have to concern themselves with. Personally,
>> >> the amount of data you can store on a Bluray disk just isn't
>> >> practical for bulk storage. For a couple home videos, it's fine.
>> >> If you intend to back up your entire, multi-TB collection, there
>> >> is a time component involved that you're not considering. With a
>> >> hard drive or tape drive, you tell it to copy, and you come back
>> >> half a day and several TB later. With Bluray, you're going to
>> >> have to keep coming back every 20-30 minutes to swap disks, and
>> >> you have to do that 80+ times to equal one large hard drive. My
>> >> time is just worth more than that.
>> >
>> > That same argument would apply to flash drives, since flash units
>> > larger than 32GB (or even 16) are prohibitively expensive, and
>> > need to be changed as well.
>> >
>> > The problem with hard drives is once removed from a system they are
>> > extremely fragile, as was pointed out earlier.
>> >
>> > Tape systems are beyond what most consumers want to spend,
>> > especially if you include a SCSI controller.
>>
>> My point was that most people who aren't doing video are perfectly
>> content with the 4-16GB of commonly available flash drives. People
>> aren't using BD-Rs because the average user doesn't need that much
>> space. Flash drives are much easier, and in the volume they need,
>> much cheaper.
>>
>> Just because you can drop an optical disk without risk of damage
>> doesn't mean they're reliable. I've tried recovering from CDs and
>> DVDs before. At a couple years age, DVDs were somewhere around
>> 75-80% readable, and CDs were something far less. I don't expect
>> BD-Rs to be any different. The organic dyes fade over time, and
>> that's assuming they haven't died already from a seal breach. If
>> you want a reliable archive, you're going to need multiple copies,
>> and you're going to need to cycle in fresh media at some interval on
>> the order of a few years. Burning that volume of BD-Rs repeatedly
>> is not a proposition I'm interested in. I'd rather take my chances
>> that I don't drop the hard drive.
>
> So no matter what method you choose, you must put up with a serious
> potential problem in some way.
>
> Risk dropping a drive, risk media degrading, do a lot of media changing
> (ie: time) or spend a lot of money. Each method seems to have some sort
> of fatal flaw, or more than one.
>
> I guess the experience with tape drives in the past has shown backup
> devices to be a hard sell to consumers, most of whom would rather have
> some new toy that gets used *now*, and not just potentially needed in
> the event of a problem that might never happen.
>
> The result is that manufacturers don't concentrate on consumer backup
> solutions, but on enterprise level backup solutions, those people having
> both the money and the motivation to pay for a good backup answer.
>
>
>
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I'm not sure I'd agree with this Brian, the reality is the explosion
in storage availability is causing huge problems even in the
commercial space.

I remember quite a few years back installing a large backup robot into
a large banking operation in Docklands, within 1 year we'd had to
install a separate LAN infrastructure to support the backups as
storage had grown so much and backups were consequently over running
on time, degrading network performance during the day. Within 2 years
we'd had to change operational procedures as users were storing their
Exchange .pst files locally and the backup runs were taking over two
days to backup one days data.  By year 3 we pulled the whole system
out and replaced it with high speed disk storage in a separate
attached building with dedicated multiple high speed network links and
multiple redundancy points on each subnet, it was the only way to keep
up with the growth in storage usage and the consequent impact on both
LAN performance and backup tapes lagging storage requirements.  The
total cost to the bank over the 3 years was just shy of 4m (and this
was 10 years ago) in what they threw away, the 4m didn't include the
cost of the replacement attached building disk storage facility.

As others have said on this list once you start getting into Multi TB
storage there is no practical solution IMHO except disk storage, if
your data is that important to you make multiple copies and store
offsite in two separate locations.  The practicality and cost savings
of buying say 6 2TB drives (at say about $100 each so $600 total) to
backup 6TB of data far outweighs the time demands, practical issues
and cataloguing problems of requiring 120 50GB BluRay disks (at a cost
of about $3 per disk - if you can find 50GB media for this price and
they won't be RE's so $360 total, not accounting for wasted burns) to
make just one backup of your 6TBs of storage.

If anyone asked me the way to go my answer would be simple.

1.  If the original data is that important to you then RAID6 it, if
the data's critical RAID60 it.
2.  If backups are important to you use high storage capacity disks,
take multiple copies and store offsite.
3.  If time is important to you there's no practical alternative
without spending large sums that may well become redundant in a short
timescale.

Just my 2c but based on nearly 30 year of commercial IT experience.


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