[mythtv-users] 3TB...poof

[Matt Dorsch]

If you made a list of the possible causes of the failures, MythTV shouldn't
be on the list. It has no control over the correctness of the filesystem.
That would be the OS's job.

If the drive passes a read-only test, which only checks if each sector can
be read successfully not the contents of the sector, then either the OS had
an issue that corrupted the FS, or there was a problem with the data
channel. Both of those a pretty unlikely these days, except old hardware
might cause a data issue.

If the drive fails a read-only test, the damage goes beyond the filesystem,
either to the circuit board of the drive or the platters themselves. This
is usually caused by low quality components, old age, or bad power. If your
system is on a UPS with AVR, it's probably not bad power.

SMART can be a useful tool to see if drives are showing signs of age:
Backblaze has done some analysis to see what SMART metrics are useful when
trying to predict an impending drive failure.

https://www.backblaze.com/blog/what-smart-stats-indicate-hard-drive-failures/

Not all manufacturers use the stats in transparent ways: e.g., one of my
drives reports a Reallocated Sectors Count of 2^31 - 1.

On a different note, 5 years ago I discovered several of my drives had
failed, but the OS still kept using them. A few months later, it dawned on
me that I probably shouldn't be using the vacuum cleaner's carpet
attachment right next to the computers and external disk under my desk.

Matt

On Sun, Mar 17, 2019 at 1:41 PM Larry Finger <Larry.Finger at lwfinger.net>
wrote:

> On 3/17/19 12:21 PM, Craig Treleaven wrote:
> > So, yet again, the drive with all my recordings is unreadable.  This has
> happened to me in September 2015, August 2013 and at least one time before
> that although I’m not sure of the date.  And again this past Tuesday
> night.  I know the dates because in 2013 I started labelling drives and
> enclosures with the date purchased and I purchased these items specifically
> because of these problems.
> >
> > I’m running Myth on Mac so virtually none of you care.  However, if
> there is someone out there on OS X that has experienced this and actually
> KNOWS a solution, I’d love to hear it.  I’ve tried a number of things over
> the last several days with success.  Various versions of Apple’s Disk
> Utility.  Swapping the drive into a couple of known-good enclosures.  Tried
> TestDisk.   The closest I got was that Disk Utility would mount the volume
> even though it reported it as damaged.  But CarbonCopyCloner was never able
> to copy more than 150MB off it.
>
> What does smartctl have to say about this drive? The utility is part of
> smartmontools.
>
> I do not use OS X, but I have had a number of disk failures over the
> years. I
> finally implemented RAID on my system. I have / and /home mounted on
> RAID5, and
> /boot on RAID0, with /boot/efi not in a RAID array. Since setting up the
> system,
> I had one drive fail. Given Murphy's law, the failed drive was the one
> with
> /boot/efi, but I had a backup copy on another drive. A few minutes work
> using a
> rescue system got me back up and running with no loss of data.
>
> Larry
>
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