Backups [was Re: Is tape dead?]

Sean Caron scaron at umich.edu
Fri Sep 25 17:55:02 CDT 2015


The WDC REs are not bad drives at all but IMO Hitachi Ultrastar is the best
line going right now. I have been working with them for some time from 0.5T
through 3T under very high duty cycle and they are fairly bulletproof. The
REs will do the work, but I have seen higher failure rates on them right
out of the box and higher failure rates on them in the longer term (~3
years) versus the Hitachi. I am hesitant to trust Seagate for large scale
enterprise use though I think they are fine to use at home, in lighter duty
cycle applications or in USB enclosures, etc.

The distinction you point out is very important particularly when selecting
drives to use in constructing a RAID; it's critical to avoid those drives
that attempt to spin down or sleep when idle; this confuses the heck out of
RAID and will cause the admin (we, the builder) no end of misery... usually
it's easy to identify these drives because they are marketed as "Green" or
"energy saver" but for some of the midrange product lines ... "prosumer"
... sometimes you have to dig a little to get to the facts. I think these
Green drives are the worst thing on the market since the old Quantum
Bigfoot; I wouldn't recommend them to anyone.

I suggest starting with the keyword "enterprise SATA" and going from there
... these drives are certified for array use 24/7 and ship without any
"power saving" nonsense straight from the OEM ... the premium over a normal
consumer SATA disk is not really too awful. These generally use identical
or very closely related HBAs to the premium SAS disks but just with
different SATA-only formatter board. No real need to go SAS unless you
require multipath.

Best,

Sean


On Fri, Sep 25, 2015 at 4:56 PM, Alexander Schreiber <als at thangorodrim.ch>
wrote:

> On Thu, Sep 24, 2015 at 11:33:59PM -0700, Chuck Guzis wrote:
> > On 09/24/2015 04:30 PM, Alexander Schreiber wrote:
> >
> > >IMHO, you want to buy at one generation below the current max
> > >capacity on the assumption that they ironed out the bugs on that
> > >one.
> >
> > So, if you were to move up from the 500GB SATA drives to the "next
> > generation", which would you choose?
>
> My last set of drives where WD Red 2TB drives. They are designed for NAS,
> so can deal with 24/7 operation. One word of warning on those: by default
> they spin down on idle (and spin up again on access). In a typical light
> loaded environment, that is likely to run up the load cycles sky high
> in a hurry. So I recommended completely disabling that (note: after
> changing this setting, the drives need a power cycle).
>
> Older ones: I'm quite fond of WD RE series drives, a bit more expensive
> but from my experience very reliable.
>
> Kind regards,
>            Alex.
> --
> "Opportunity is missed by most people because it is dressed in overalls and
>  looks like work."                                      -- Thomas A. Edison
>


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