Re: Rebooting and HDD spinup / spindown cycles [WAS: Re: Debian Wheezy - HP Pavilion dm1]
On 2013-10-23, Ralf Mardorf <ralf.mardorf@alice-dsl.net> wrote:
>
> Isn't that plausible? I'm the source, I care for facts, not for claims
> from vendors.
>From your favorite company:
<research.google.com/archive/disk_failures.pdf>
Power Cycles. The power cycles indicator counts the
number of times a drive is powered up and down. In
a server-class deployment, in which drives are powered
continuously, we do not expect to reach high enough
power cycle counts to see any effects on failure rates.
Our results find that for drives aged up to two years, this
is true, there is no significant correlation between fail-
ures and high power cycles count. But for drives 3 years
and older, higher power cycle counts can increase the
absolute failure rate by over 2%. We believe this is due
more to our population mix than to aging effects. More-
over, this correlation could be the effect (not the cause)
of troubled machines that require many repair iterations
and thus many power cycles to be fixed.
Power-on hours. Although we do not dispute that
power-on hours might have an effect on drive lifetime,
it happens that in our deployment the age of the drive is
an excellent approximation for that parameter, given that
our drives remain powered on for most of their life time.
Key findings:
· Contrary to previously reported results, we found
very little correlation between failure rates and ei-
ther elevated temperature or activity levels.
· Some SMART parameters (scan errors, realloca-
tion counts, offline reallocation counts, and proba-
tional counts) have a large impact on failure proba-
bility.
· Given the lack of occurrence of predictive SMART
signals on a large fraction of failed drives, it is un-
likely that an accurate predictive failure model can
be built based on these signals alone.
Reply to: