What an entertaining discussion! Hope the following adds to the
entertainment value :).
Any comments on this Dec. 2005 study on disk failure and error rates?
http://research.microsoft.com/apps/pubs/default.aspx?id=64599
Seagate says their 1.5TB consumer grade drives are good for 24*365
operation. http://labs.google.com/papers/disk_failures.pdf implies yes.
This paper is quite interesting. Power cycles - bad. High temps - not
so bad...
The specs say an annualized failure rate of 0.34% and mean time between
failures of 750,000 hours. 8760/750,000 = 1.17%. Hmmm. So around one
disk in a hundred will fail each year? What does that mean to a system with
a simple mirror if one disk in 20 will fail in 5 years?
What is the MTTDL of a mirrored pair of consumer grade 1.5TB drives,
or the probability of a single data loss (say) during a 5 year period,
perhaps compared to the probability (say) of winning the lottery :-),
or being hit by a 20 ton meteor, assuming at least one device failure?
The OP originally asked "Best 1.5TB drives for consumer RAID?". Despite
the entertainment value of the comments, it isn't clear that this has been
answered. I suspect the OP was expecting a discussion of WD vs. Seagate
vs. Hitachi, etc., but the discussion didn't go that way, perhaps because
they are equally good (or bad) based on the TLER discussion? Has anyone
actually experienced an extended timeout from one of these drives (from
any manufacturer) causing a problem?
On 01/24/10 11:26 AM, R.G. Keen wrote:
The most durable data backup medium humans have come up with was
invented about 4000-6000 years ago. It's fired cuniform tablets as
used in the Middle East. Perhaps one could include stone carvings of
Egyptian and/or Maya cultures in that.
Just trying to picture 1.5TB of data as cuniform tablets :-).
On 01/24/10 12:44 PM, Tim Cook wrote:
10%? I'm not sure where you shop, but no. The cheapest 500GB is
$39.99. The cheapest 1.5TB is $97.99.
$359.91 for the 500GB drives.
$391.96 for the 1.5TB drives.
You are comparing 9*500GB vs. 4*1.5TB? Wouldn't you need
12*500GB for an apples-to-apples comparison? Surely a
3-way mirror is very unlikely to lose any bits under any
reasonable scenario (see above pdfs).
$97.99 * 3 = $293.97. Also, since newer drives tend to use less
absolute power, 9*500GB drives are probably going to use
significantly more than 3*1.5TB drives. perhaps 4 or 5 times as much;
they'd be proportionately more difficult to cool too, which might
reduce reliability. 16.5W (ST31500541AS) vs. 75W (WD5000AAKS)
when idle - that's about $50/year at $0.10 per KWH, not including
cooling + extra controllers, fans, and a beefier power supply. Sounds
like much more than a $200 advantage over 3 years, enough for 2
more 1.5TB drives for backups/spares. Does the 32GB vs 8GB of
cache count for anything?
On 01/23/10 04:20 PM, Richard Elling wrote:
My theory is that drives cost $100. When the price is> $100, the drive is
manufactured. When the price is< $100, the drive is EOL and the manufacturer
is flushing the inventory. Recently, 1.5 TB drives went below $100.
Yes, for Seagate, a newish model, ST31500541AS (5900RPM 1.5GB drive).
AFAIK the older ST31500341AS (7200RPM 1.5GB drive) is still over $100.
The 2 month or so old ST31500541AS can hardly be EOLed at this point!
However, it escapes me why anyone would not want to spend the extra $10
for the faster and more mature drive unless power consumption is important.
On 01/23/10 01:15 PM, Bob Friesenhahn wrote:
This looks like a really good drive for use with zfs. Be sure to use a
Aren't /all/ drives good for use with ZFS? Personally, AFAIK, I've never
lost a single bit of data using ZFS, even using grotty hardware (well, had
to use copies=2 on a mirror of very old IDE drives, but what other FS
lets you do that?).
mirror configuration and keep in mind that zfs supports an arbitrary
number of mirrors so that you can run six or ten of these drives in
parallel so that there are enough working drives remaining to keep up
with RMAed units.
You seem to have it in for Seagate :-). Newegg by default displays reviews
worst to best. The review statistics as of 23 Jan 2010) were:
ST31500341AS (older, 7200RPM 1.5GB drive)
Excellent 911 - 49%
Good 233 - 12%
Average 113 - 6%
Poor 123 - 6%
Very Poor 514 - 27%
ST31500541AS (more recent, 5900RPM 1.5GB drive).
Excellent 64 - 35%
Good 26 - 15%
Average 11 - 6%
Poor 14 - 8%
Very Poor 64 - 36%
The approval rate seems to get better as the product matures, surprise,
surprise. Also, many of the "Very Poor" seemed to have problems
that are not the fault of the drive ("stuck at 73% of capacity...").
Be sure to mark any failed drive using a sledgehammer so that you don't
accidentally use it again by mistake.
In my experience, failed drives rarely resuscitate themselves :-), so it's
pretty easy to tell them apart. However every Seagate 1.5TB drive ever
sold is still under warranty, so I suggest rather than smashing them,
RMA them. They don't seem to be that bad, based on the professional
reviews - actually some are almost ecstatic. Has anyone reading this who
uses them had one fail?
Cheers -- Frank
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