[TriLUG] SCSI vs. SATA in theory

[Kevin Flanagan]

We had HP server engineering staff in here a little while back.  They are
making most of the Proliant line, the 300 series at least, available as
SATA or Parallel SCSI now, and moving in the direction of Serial SCSI over
the long term.


We asked the engineering team about SATA vs SCSI and the MTBF etc, they
said that their testing shows about 1/2 of the MTBF for ATA/SATA.   That's
not so good, we have a load of Proliant DL360's going out, about 1200 of
them over the next year.  We also learned that the Warranty of the SATA
disks is only 1 year, where the Warranty on the SCSI disks are 3 years, if
you expect to keep these things up for years, you really should just go
with the SCSI disks.


The performance of SCSI is still generally faster, SATA makes headway, but
now there's Serial SCSI on the horizon, SCSI should widen the performance
gap once again.



Kevin





> sata drives are not substantially different from traditional ide drives,
>  they just have a different controller and interface.  the only
> exception that i know of are the wd raptors which are aimed at the
> enterprise market and cost about the same as scsi.
>
> therefore, if reliability is truly a concern and you want to do the job
> right, then you really only have one option - scsi.  and since that
> isn't 100% foolproof, you still need backup of some sort.  use sata/ide
> for that purpose - dense, cheap, and if it fails you haven't lost
> anything.  but if reliability is the goal, stick with scsi.
>
> jason
>
> On Thursday 10 February 2005 14:32, Greg Brown wrote:
>> Do mean time between failure rates between SCSI and SATA differ
>> greatly in the field?  Most IDE drives seem to live 3-5 years under
>> moderate use and I'm fairly certain that SCSI can go much further then
>> that, but what about SATA?  I have to spec out my home server that I
>> want to build once the wife's bonus arrives and I'm thinking about
>> drives.  I have lots of OLD data that I could probably part with (old
>> laptop files from companies I no longer work for, etc) but I don't
>> want to - you never know when those five year old Lucent files might
>> come in handy!
>>
>> :)
>>
>> I've been looking towards SATA for the large-volume storage and
>> thinking about SCSI for my heavily used partitions (web, database,
>> tmp).
>>
>> Does adding a SCSI drive just for high duty-cycle partitions rally
>> matter?  Can I get away with just having everything on one, big SATA
>> drive?  I normally only get  one chance over five years to build a
>> really nice server, so I want to get this right.
>>
>> Greg
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