[Gllug] Maintaining music libraries in various formats

[Nix]

On 22 Aug 2009, Chris Bell stated:
> On Fri 21 Aug, Nix wrote:
>> I have four 1Tb drives in my larger Nehalem (bought in May). They cost
>> less than the disk controller they're attached to (admittedly, mainly
>> cos it's a hardware RAID controller with a whopping cache).
>
>    There was a report that a large cache may lead to lazy writing where
> edits hit the real disc in the wrong order and cause data corruption. Some
> discs were found to even ignore requests to complete a write immediately and
> just indicate that the write was completed because it gives the impression
> of speed to keep the advertisers happy.

The disks are WD GreenPower: they actually sacrifice speed for power
efficiency. GreenPowers have a bad rep under Linux because they spin
themselves down by a few krpm after a few seconds with no access, which
interacts badly with ext3's habit of syncing every five seconds. I don't
care, because I'm using ext4, which doesn't flush so often, and 'cos the
controller is an Areca with half a gig of battery-backed cache (and an
annoying beep if the power goes out with the cache unflushed), and the
machine has so much RAM that reads of commonly-accessed data are rare.
So I don't give a damn what order the drives choose to do things in:
modulo controller bugs, as soon as it hits the controller, it is on the
disk, or might as well be; and the drives can stay spun down for some
time before being woken up with a giant tranche of work to do.

(My only worry is that I'm not sure how well the battery will last. The
docs say five years, but I expect this machine to last longer than
that...)
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