[CentOS] Software RAID1 with CentOS-6.2

Chuck Munro chuckm at seafoam.net
Thu Mar 1 13:13:03 EST 2012


On 03/01/2012 09:00 AM, Mark Roth wrote:
>
> Miguel Medalha wrote:
>> >
>> >  A few months ago I had an enormous amount of grief trying to understand
>> >  why a RAID array in a new server kept getting corrupted and suddenly
>> >  changing configuration. After a lot of despair and head scratching it
>> >  turned out to be the SATA cables. This was a rack server from Asus with
>> >  a SATA backplane. The cables, made by Foxconn, came pre-installed.
>> >
>> >  After I replaced the SATA cables with new ones, all problems were gone
>> >  and the array is now rock solid.
> Thanks for this info, Miguel.
> <snip>
>> >  As an additional information, I quote from the Caviar Black range
>> >  datasheet:
>> >
>> >  "Desktop / Consumer RAID Environments - WD Caviar Black Hard Drives are
>> >  tested and recommended for use in consumer-type RAID applications
>> >  (RAID-0 /RAID-1).
>> >  - Business Critical RAID Environments ? WD Caviar Black Hard Drives are
>> >  not recommended for and are not warranted for use in RAID environments
>> >  utilizing Enterprise HBAs and/or expanders and in multi-bay chassis, as
>> >  they are not designed for, nor tested in, these specific types of RAID
>> >  applications. For all Business Critical RAID applications, please
>> >  consider WD?s Enterprise Hard Drives that are specifically designed with
>> >  RAID-specific, time-limited error recovery (TLER), are tested
>> >  extensively in 24x7 RAID applications, and include features like
>> >  enhanced RAFF technology and thermal extended burn-in testing."
> Wonderful... NOT. We've got a number of Caviar Green, so I looked up its
> datasheet... and it says the same.
>
> That rebuild of my system at home? I think I'll look at commercial grade
> drives....
>
>         mark
>
Interesting thread ... I have had problems with SATA cables in the past, 
and prefer those with the little metal latches.  The problem is that you 
can't easily tell by looking at the connectors whether or not they're 
flakey.

I've had positive experience with Caviar Black and Scorpio Black drives.

The WD Green and Blue drives are built more cheaply than the Blacks 
(which have close to enterprise-grade construction).  The dealer I buy 
drives from has told me that the Blacks have far lower return/defect 
rates.  Of the approximately 30 2TB Blacks I have in RAID-6 service, 
I've only experienced two failures, which were handled quickly by the WD 
warranty program.  It's interesting to note that while all the drive 
manufacturers are going back to 1 or 2-year warranties, the WD Black 
series remains at 5 years.

A friend of mine has had a couple of strange problems with the RE (RAID) 
series of Caviars, which utilize the same mechanics as the non-RE 
Blacks.  For software RAID, I would recommend that you stick with the 
non-RE versions because of differences in the firmware.

It has come down to me buying *only* WD Black-series drives and nothing 
else.  If I could afford them, I'd consider enterprise-grade drives.

Having said that, I have a pair of 1TB Green drives in RAID-1 for the 
TimeMachine backups on my Mac, and they've been spinning 24x7 non-stop 
for 3 years without failure.  I'm almost afraid to switch them off.

Now, if WD can just get their post-flood production back in gear so 
prices can drop.  My 2c, FWIW  :-)

Chuck


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