mixing IDE and SATA hard drives on a FreeBSD system

[Chad Leigh -- Shire.Net LLC]

On May 4, 2005, at 10:15 PM, jason henson wrote:

> Chuck Robey wrote:
>
>
>> David Kelly wrote:
>>
>>
>>> On Wed, May 04, 2005 at 03:22:25PM -0500, Andrew L. Gould wrote:
>>>
>>>
>>>> I was thinking about putting FreeBSD and swap on the ATA100 IDE  
>>>> hard drive and installing a SATA hard drive for home and  
>>>> database data.  Is there any reason I shouldn't mix hard drive  
>>>> types?  (I've never messed with SATA before.)
>>>>
>>>
>>>
>>>
>>> I have one PATA with FreeBSD installed, and two SATA striped with
>>> gvinum. Swap spread across all 3. No particular problems. The SATA
>>> drives are fairly recent models in 160G, the PATA is prior  
>>> generation in
>>> 120G, all Hitachi. The SATA drives seem to handle seeks from  
>>> multiple
>>> processes better than the PATA, better even than might expect from
>>> striping.
>>>
>>> At about 4500 hours of runtime one SATA drive developed a bad block
>>> which the drive firmware was not able to automagically  
>>> substitute. gvinum
>>> shut down.
>>>
>>> I see no reason why a SATA drive should be less reliable than a PATA
>>> drive. Also remember back when one could purchase the same drive
>>> hardware in either PATA or SCSI, so find it hard to accept the  
>>> interface
>>> makes much difference in reliability.
>>>
>>>
>> I don't know why it's true... I can state that I've had 3 of them  
>> so far, and had troubles with 2, and google is chock full of  
>> reports. Further, the info about them being the same as their IDE  
>> brethren isn't true, at least, the access rate specifications are  
>> higher for SATA drives, in general, as compared to IDE.  Least  
>> they were the last time I checked, maybe it's changed inthe last 6  
>> months.
>>
>> OTOH, when I first bought mine, I was comparing in my mind with  
>> SCSI, not IDE, maybe they *do* compare equally with IDE, is IDE  
>> that bad? Certainly, SATA is less reliable thant he scsi drives.
>>
>>
> Don't compare IDE to SCSI.  IDE is home/consumer grade.  SCSI is  
> commercial/enterprise grade.  Just look at the price differences,  
> because you most certainly get what you pay for with SCSI compared  
> to IDE.
>
> **Warning, the following contains anecdotal evidence**
> I built a new rig for my brother with SATA and it has been  
> perfect.  I only have IDE in my slightly older machine which runs  
> great 24/7.  But this has just been my experience, as always YMMV.
> One last thing, I would avoid the first generation of most  
> technology because they tend to still have some bugs.  So if you  
> buy SATA don't et the discounted drive, look for a newer model and  
> you should be good.  Also checkout storagereview.com
>

Most of the first generation SATA drives were actually PATA (aka IDE)  
drives with a separate SATA <-> PATA converter added (at the board  
level).  Some newer SATA drives have native SATA interfaces and it is  
possible that the manufacturers do not make a PATA version of the  
same drive, but in most cases, SATA drives have PATA brethren and  
these PATA brethren have the same mechanisms.  There are exceptions,  
and the WD Raptor series of SATA drives are more like SCSI in terms  
of performance and MTBF numbers, and they were designed for the same  
market as the lower end enterprise SCSI drives.

Chad


---
Chad Leigh -- Shire.Net LLC
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