[TriLUG] Disk drive recovery services

[Wes Garrison via TriLUG]

One drive had ~60,000 reallocated sectors, then the servo motors failed in
2 more while resilvering.  Low Cost Recovery was able to transplant the
motors (or heads, I can't remember which) 2 recover the data from the 2
with failed motors/heads.  I think the 60k bad sector drive was trash,
IIRC.  The head was scraping over the platters and ruined whatever data was
there.

When looking this up, I posted this on this very list in October 2014(!!!).

Also, 7 of the original 8 ST3000DM001 Seagate drives died, not 6.  I only
have 1 still going; the rest have been replaced with WD Reds.

On Tue, Sep 22, 2020 at 10:54 PM David Burton <ncdave4life at gmail.com> wrote:

> When you said that three drives failed, how badly have they failed?
>
> Are they casters-up dead-as-doornails?
>
> Or just limping, with some bad sectors?
>
>
> On Tue, Sep 22, 2020 at 5:26 PM Wes Garrison via TriLUG <trilug at trilug.org>
> wrote:
>
>> Joe,
>>
>> It wasn't the fault of ZFS.  I was using the notorious Seagate
>> ST3000DM001,
>> which is a consumer drive not meant for NAS (not meant for much of
>> anything
>> really).
>>
>> Out of the original 8, only 2 remain.  Worst failure rate I've ever seen.
>>
>> I was using a ZFS Z2 array (which can support 2 simultaneous failures),
>> and
>> had 3 simultaneous failures; the latter 2 occurring during re-silvering.
>> This is pretty common, apparently.  When you have a failure and start
>> hammering the drives to do a rebuild, you often have more failures.
>>
>> Lessons learned:
>> 1) Use NAS drives or Seagate Exos for RAID/ZFS arrays, not crappy consumer
>> drives.  If you buy WD, make sure you get CMR and don't get fleeced with
>> SMR drives.
>> 2) use ZFS Z3 for better fault tolerance
>> 3) have an actual backup if practicable.  This is hard when your array is
>> huge.  How do you back up an 18TB array when the largest available
>> consumer
>> drive is 4TB?  With another 18TB array, of course!
>>
>> -Wes
>>
>>
>> On Tue, Sep 22, 2020 at 4:18 PM Mauricio Tavares via TriLUG <
>> trilug at trilug.org> wrote:
>>
>> > On Tue, Sep 22, 2020 at 4:15 PM Joseph Mack NA3T via TriLUG
>> > <trilug at trilug.org> wrote:
>> > >
>> > > On Tue, 22 Sep 2020, Wes Garrison via TriLUG wrote:
>> > >
>> > > > He was able to do head transplants on multiple drives that were part
>> > of a ZFS
>> > > > array and I was able to recover almost all of the data.
>> > >
>> > > I'm just starting out on zfs (at home) and I have little idea what
>> > horrible
>> > > things can happen to zfs or how I'm going to recover from them if they
>> > do. I
>> > > thought that no much could go wrong with zfs. So what happened to your
>> > zfs
>> > > array?
>> > >
>> >        To have truly horrible things  happen to your data you need a
>> Drobo.
>> >
>> > > Joe
>> > >
>> > > --
>> > > Joseph Mack NA3T EME(B,D), FM05lw North Carolina
>> > > jmack (at) wm7d (dot) net - azimuthal equidistant
>> > > map generator at http://www.wm7d.net/azproj.shtml
>> > > Homepage http://www.austintek.com/ It's GNU/Linux!
>> > > --
>> > > This message was sent to: raubvogel at gmail.com <raubvogel at gmail.com>
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>> > that address.
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>> > --
>> > This message was sent to: Wes <wes at xitechusa.com>
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>> that
>> > address.
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>> > Welcome to TriLUG: https://trilug.org/welcome
>> --
>> This message was sent to: Dave Burton <ncdave4life at gmail.com>
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>
>