Re: [gentoo-user] Are those "green" drives any good?

["mike@trausch.us" <mike@trausch.us>]

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On 05/09/2012 07:47 AM, Tanstaafl wrote:
> As long as you don't use them in any kind of RAID setup you they should
> be fine.
> 
> The biggest difference between them and 'enterprise' class drives is the
> enterprise class drives are designed for multi-drive RAID setups... you
> don't want drives to spin down independently when working in a RAID
> setup...

AFAIK, the only technical difference between a consumer drive and an
enterprise one is that the enterprise one doesn't tell lies.  Or at
least, it isn't supposed to.

Consumer drives will acknowledge writes before they have hit the
platter, even if the cache is disabled on the drive (and some consumer
drives do not even allow the cache to be disabled).

The only scenario this seriously guards against is unexpected power
loss, where the drive has told the OS that the data has been written to
disk, but it is somewhere in-between (e.g., on cache, but not on the
platter) and then the power is disconnected from the unit (specifically,
the drive itself).  Even an unexpected reboot from the computer won't
affect this, unless the computer removes power to the device during
early boot (and on x86 systems, that is a virtual impossibility).

	--- Mike

-- 
A man who reasons deliberately, manages it better after studying Logic
than he could before, if he is sincere about it and has common sense.
                                   --- Carveth Read, “Logic”


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