[rescue] 36G SCA drives still looking

[Charles Shannon Hendrix]

Fri, 04 Mar 2005 @ 12:01 -0500, Patrick Giagnocavo said:

> On Fri, Mar 04, 2005 at 10:41:06AM -0600, erie wrote:
> > The only thing that worries me about SATA drives is that the hda is 
> > (quoting a friend of mine that works for a HD mfr) "identical to the 
> > ones used in our IDE line"..
> 
> Yes, they basically ARE exactly the same aside from the connector.

That's not true for all of them.

A "real" SATA drive is not an IDE drive.

Some IDE drives are sold with an IDE-SATA bridge and sold as SATA, but
they really aren't.

SATA is of course compatible with ATA protocol, which is itself just a
subset of SCSI.

> > anyone notice how long ata drives last these days? I've got 10+year old 
> 
> As I understand it, the bearings are not stainless steel balls, but an
> oil-based bearing.  Over time the oil will leak out, and either the
> bearing will fail or the oil will end up somewhere else, i.e. on the
> platter.

This has *nothing* to do with IDE.  SCSI drives use fluid bearings
too now, and one of the reasons given by Seagate is to *increase*
reliability.  

Seagate uses fluid bearings in their high end SCSI drives, even very
expensive 15K rpm drives.  One hopes they aren't going to start dying.

Early fluid bearings did fail a lot, and Maxtor's Diamond drives with
fluid bearings were a huge problem, but Seagate in particular says that
problem is in the past.  Hopefully they are right.

I did a bit of googling on fluid bearings.

Cons:

    - fluid bearing failure is caused by over-lubrication, and early
      poor designs
    - fluid bearing failure is caused by overheating, due to lubricant
      evaporation
    - fluid bearing failure is caused by insufficient motor seals which
      allow dirt, soot, and water into the bearings
    - fluid bearings in Maxtor drives cause vertical vibration which
      destroys the service area of the disk, on earlier Diamond
      families

Pros:

    - most fluid bearing designs have been greatly improved since their
      first introduction
    - good fluid bearings increase drive life because of lower
      vibration, for both physical and electronic parts
    - fluid bearings reduce heat, sometimes a lot, which can also
      increase drive life
    - steel bearing drives gradually increase noise, heat, and vibration
      as they wear out... wether or not it is a problem depends on
      a lot of factors
    - fluid bearings reduce friction, resulting in longer motor and
      power supply life (in the drive), and reduce power consumption

It looks to me like it was a technology with some early growing pains.

With Seagate using fluid bearings in their most expensive SCSI drives
now, it seems they are pretty confident they are OK.

Of course, that doesn't mean that people like Maxtor have it working
right.

> I have had pretty good success with both IDE and SCSI drives.  Backups
> however are always a good idea :-)

Amen.

Also, check your drive status now and then.  Most good drives give you
warning before failure.


-- 
shannon "AT" widomaker.com -- ["An Irishman is never drunk as long as he
can hold onto one blade of grass and not fall off the face of the earth."]