drive selection for disk arrays

Arthur Chance freebsd at
Thu Mar 26 09:22:05 UTC 2020

On 25/03/2020 22:19, David Christensen wrote:
> Jacques Foucry wrote:
>> ALWAYS (when it's possible) buy and use disks from different brand
>> (mix seagate, WD, etc..) in order to avoid same series and same MTBF.
>> I know this to late in this case, but keep this in mind.
>> I know this will not help in this case, please excuse my
>> intervention if it's inappropriate.
> To date, most of my arrays have been composed of similar drives.  But, I
> run a SOHO LAN and have limited experience.  I have been wondering about
> using dissimilar drives to prevent simultaneous common-mode failures.
> Backblaze publishes statistics for individual drives:
> I would be curious to read any data or reports comparing arrays of
> similar drives vs. arrays of dissimilar drives.
> Have anyone seen a failure involving multiple similar drives all failing
> in the same mode at the same time?

Not at exactly the same time, but the first time I ever built a zraid
array, shortly after zfs was first released, I used a batch of four
identical disks. About 5-6 years later they all failed over a period of
about 2-3 months. There was long enough between failures to buy a
replacement drive on next day delivery and recover, but this was on a
home file server, not a heavily loaded system. Nowadays I buy from a
couple of manufacturers based on Backblaze's latest statistics.

Violets are red
And roses are blue
When metamaterials
Alter their hue.

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