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[ale] Best 2TB drives to extend my RAID array?

> On Thu, 2011-03-03 at 09:46 -0500, I wrote:
>> My 1.8TB RAID(10) array is close to filling, and I'm looking to buy
>> some additional drives to extend it.  I was thinking that I'd buy a
>> pair of 7200RPM 2TB drives to effectively double my raid size, which
>> should last me several years at the current usage rate.  Anyone have
>> recommendations for currently-available drives?  All else bring equal
>> I'm thinking about buying this drive:
>>   http://www.newegg.com/Product/Product.aspx?Item=N82E16822145473
>> Has anyone else been in the market for large drives and/or have
>> opinions?

scott <scott at sboss.net> writes:
> I have been buying Seagate 2TB SATA drives for ~$79 from NewEgg.
> Seagates seem to work very well. And their customer service team is
> very responsive if you have issues.

The $79 Seagate drives appear to be 5400RPM, not 7200RPM.  The cheapest
2TB 7200RPM Seagate is $170.  I'd prefer to stay with 7200RPM drives, I
think, for speed.

"Michael B. Trausch" <mike at trausch.us> writes:
> Just keep in mind that HDDs have the same failure rates (in terms of the
> physical platters) as similar drives of smaller capacity in the last
> several years.  That means that the probability that you will encounter
> significant errors is vastly increased.
> An error in the physical space that 1 sector took up in a 120 GB drive
> is likely to be an error that sits in the space of a great many sectors
> on a 2 TB drive.  It's unlikely that the spare sectors area is much
> larger than in older drives, as well, though I cannot say for sure
> either way.

Sure, but that's also why you run RAID and smart.  I've currently got
four 1TB drives in my array and haven't had any errors, yet.  But I
suspect it's getting close to the time where I need to think about
proactively replacing them.

> Just plan for failure on drives that big and you should be fine.  How do
> you backup such a large amount of data on a regular basis?

Yep, I like having a cold-spare drive on hand, just in case.  Most of
the data on the drives are just local mirrors of stuff on the net so I
don't worry about backing that up because I can always re-mirror it.

Some data I mirror off-site.  But honestly I don't have a good backup
system in place.

Robert <rs at ale.spam.futz.org> writes:
> I'd recommend that you buy drives from two different manufacturers... I
> used to buy matched pairs, till I had a raid1 array go south with failures on
> both drives. :-(  I also recommend a complete read/write badblock check and
> running SMART diagnostics before putting the new drives in service.

Yes, I definitely plan to run a full disk read/write burn-in test before
turning it live in my RAID array.  However, it sounds like most of the
problem with the Hitachi drives are DOAs, usually due to shipping
issues.  So if they make it to me alive then the drives will probably be
okay.  But yes, definitely need to run a burn-in.

As for matched pairs, I understand why you say it, but having
non-matched pairs can wreak havoc on some RAID systems because the
drives don't perform similarly.  But you're right that multiple drives
of the same type have similar MTBF characteristics and will probably
fail around the same time.

So back to my original question:  It sounds like Seagate is popular.
Historically I personally like Hitachi drives; I've had issues with
Seagate and WD drives in the past.

Does anyone know anything about the Hitachi 7K2000 versus 7K3000 2TB drives?


       Derek Atkins, SB '93 MIT EE, SM '95 MIT Media Laboratory
       Member, MIT Student Information Processing Board  (SIPB)
       URL: http://web.mit.edu/warlord/    PP-ASEL-IA     N1NWH
       warlord at MIT.EDU                        PGP key available