[GLLUG] Disk drive controller question

Fri Feb 6 17:43:57 EST 2009

Nope.  Not accounted for.  We have to copy a partition from B to A  
from each controller.  Could be some low level problem with the drive,  
how the partition table worked out on one vs. the other, or how you've  
got one of the cables routed when it gets hooked to the other drive.

You're right that caching really should not be an issue over the  
period of sustained read/write we're discussing.

As a tech guy for many years, when I see hoof prints, I think horses,  
not zebras.  It is very likely that you are dealing with something  
mundane and ordinary. (like a drive that ain't happy for some reason,  
or one controller's immunity OR sensitivity to some kind of noise) as  
opposed to something really out of the ordinary.  (like cosmic rays or  
other stellar phenomena)  Something that's unusual doesn't necessarily  
mean genuinely *weird*.

Statistics aren't worth much by themselves.  Statistics based on my  
own experience, I tend to believe.  And somewhere between 80% and 90%  
of what I see are relatively simple problems.  Good troubleshooting  
will ALWAYS get you to the source of the problem.  You have yet to do  
more than half the work for eliminating the drives themselves as an  
issue.  When PC's (of any variety) go funky or act unusually, the vast  
majority have issues with power supply or disk drives.  Period.  ALL  
of the rest of the problems account for only 1 or 2 out of 10 repairs.

Again, it's a matter of whether you actually care to find out or  
not.   I merely suggested possibilities for elimination.  You're  
welcome to try or not at your own discretion.  I heartily endorse  
Spinrite for anyone to use on any system.  It doesn't replace backup,  
but it obviates the need for disaster recovery much of the time.

-B

On Feb 6, 2009, at 4:41 PM, Stanley C. Mortel wrote:

> Points 1 and 2 have already been accounted for.  Copy partition on A  
> attached to on-board IDE to B attached to 3WARE: takes 5 minutes.   
> Now just disconnect the cables at the drives and swap them around.   
> Copy partition on A attached to 3WARE to B attached to on-board  
> IDE:  takes 2 hours.  Point 3 is, I suppose, possible, but the on- 
> board IDE controller works just fine and isn't THAT old.  If it  
> could only write about 1/24th as fast as the 3WARE card then either  
> the system would suck in normal operation or the 3WARE card would be  
> worth a lot of money.  Besides that, the on-board IDE controller  
> would have to be only writing at 1/24th of what the drive is capable  
> of.  I haven't taken a look at the specs of the drive, but, again,  
> the system and IDE controller are not that old, and they work as  
> expected.  Also, they are both on the same PCI-33 bus.  I may be  
> that the 3WARE card is caching a bunch, but for a sustained transfer  
> like this, that wouldn't account for the difference.
>
> I think.
>
> Stan
>
>
>
> Bill Bartilson wrote:
>>
>> One is obviously faster than the other.   :)
>>
>> All kidding aside, if you want to shed light on what the actual
>> differences are:
>>
>> 1.  Swap the drives.  I know you say they are identical, but they
>> can't be.  Each drive has different physical parts.  One drive might
>> be dying, one might be healthy.  At any rate, it's only science if  
>> you
>> can duplicate it.  Mark one 'A' and one 'B' and try each on each
>> different controller, copying each way, and note any differences, and
>> whether the differences follow the drive or not.
>>
>> 2.  Repeat the same deal with each other item.  (IDE wires, different
>> jumper settings on the drive, anything else you can think of to
>> change.)  Keep good notes.
>>
>> 3.  Try a different piece of software (Gparted or something)  Perhaps
>> the code written for reading data with controller X works much better
>> with controller X, but only for long reads, and works like crap for
>> long writes.  I dunno.
>>
>> Via process of elimination, you'll discover that one controller reads
>> or writes a lot faster, one of the drives is actually not so good, or
>> something in the code itself is different.
>>
>> This all presumes it's not merely an intellectual question and you
>> care to 'know' the answer.  I for one would be interested to hear  
>> your
>> findings if you care to try.
>>
>> Me thinks the most likely scenario is that one of the drives is
>> getting funky.  In which case I'd say Spinrite them both before you
>> try anything else.
>>
>> Regards,
>> B
>>
>>
>> On Feb 6, 2009, at 2:35 PM, Stanley C. Mortel wrote:
>>
>>
>>> OK, here's the deal.  I'm using Acronis to copy a partition from one
>>> IDE
>>> drive to another identical drive, both are 120 GB with a single
>>> partition.  One drive is connected to the on-board IDE controller,  
>>> the
>>> other is connected to a 3WARE RAID controller with only one drive on
>>> it.  Each drive is alone on its channel / cable, set to cable
>>> select, on
>>> the right connector, etc.  If I copy from the IDE to the 3WARE, it
>>> takes
>>> about 5 minutes.  If I try it the other way around, it tells me it  
>>> is
>>> going to take 2 hours.  There is nothing in my knowledge base to
>>> explain
>>> this.  Anyone know why this would happen?  If you don't know for  
>>> sure,
>>> any reasonable ideas?
>>>
>>> Stan
>>>
>>>
>>> _______________________________________________
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>>> linux-user at egr.msu.edu
>>> http://mailman.egr.msu.edu/mailman/listinfo/linux-user
>>>
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