"Michael Giegerich" <migieger (AT) web (DOT) de> wrote

Sounds like they made a lemon and still try to sell it without fixing it.
If it wasn't designed to be able to do this then it simply wouldn't let
you do it.

How was it worded? Were they just warning people not to do something
obviously dumb like combining SAS and SATA drives into the same array?

If they are saying not to have a SAS array and a separate SATA array on the
same controller then I agree with Frank

John L Rice

In article <0ksi1f.2e31.ln (AT) luva (DOT) dyndns.org>, migieger (AT) web (DOT) de says...
not supposed to put both SAS & SATA drivers into the same array
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Michael Giegerich wrote:

I don't know if this is the reason, but mechanical systems tend to
resonate. If, for example, you put a bunch of similar pendulum clocks
in a room, after a while all will have the same period.

Generators will sync together, motors will run at the same speed.

I can see that having a 7200 RPM and 15000 RPM motor in close proximity,
especially in a computer case which vibrates, could cause problems...

So I agree with you, it's weird but I can see the sense.

Maybe it's lawyer-ese for "If the drives fail and they're not on the
same controller, you can't blame us. If they're on the same controller,
you can blame us." :-|

"John L Rice" <Drummer (AT) ImJohn (DOT) com> wrote

Nonsense.

There is nothing obviously dumb about it.

Who?

Do your brainfarts happen often?

"Andy" <info (AT) evenenterprises (DOT) com> wrote

But adding them as single drives outside an array would be fine.
Yup, that obviously makes sense.

Here's another store to avoid. Thanks for the warning.

Michael Giegerich <migieger (AT) web (DOT) de> kenjka:
SATA and SCSI/SAS drives spin in different direction, that's the reason
why it's not recommended installing both type of drives in the same case...

Quotation:
Although SAS and SATA are compatible, Mike Karp of Enterprise Management
Associates cautions against mixing different drives in the same enclosure.

"Only put drives of the same speed in the same bay," he advises. "Devices
spinning at different speeds cause vibration, and there is a danger that
drives can unset or cause errors in reads and writes."

http://www.serverwatch.com/hreviews/article.php/3619016


--
"Bijesans li celavacu izdrkavu ?" upita Misko bulji Ficou pozdravlju.
"Nisam ja nikog bombardiro !" rece majoneza trci "Ja samo rostiljog ljubija blesavm !" By runf

Damir Lukic, calypso (AT) _MAKNIOVO_fly (DOT) srk.fer.hr
a member of hr.comp.hardver FAQ-team

<calypso (AT) fly (DOT) srk.fer.hr.invalid> wrote

Bwahahah (ROTFLOL).

Actually, it would be a perfect reason for doing that IF it were true
AND the vibration pattern would be rotation direction (phase) dependent.
They could actually cancel themselves out.
The reason that doesn't work is the same reason that it doesn't matter.
Even drives of same RPM can be in and out of sync, vibration wise.

A people for hire busyness.

Single drives cause vibration, drives of same model cause vibration,
drives of same speed cause vibration and drives of different speed
cause vibration too. So what. It's not that they go shake the cabinet.
If they manage to work themselves loose they are in badly designed trays.

Nothing there about drive spin directions.

uuhhmm . . . you . . . (seriously, I don't know what the hell I was
thinking. Did you ever use the name 'Frank'??)


Yeah . . .QUITE often . . it's pretty stinky here . . . . ;~?

Obviously, I'm much more proficient at lurking . . . .

"Folkert Rienstra" <see_reply-to (AT) myweb (DOT) nl> wrote

Hopefully this warning is mostly BS. I just recently finished changing my
DAW (Digital Audio Workstation) PC from using an external CRU Dataport SCSI
rack (for sale, headed soon to an Ebay listing near you) to an internal
Supermicro 5 bay SAS/SATA enclosure with two SAS drives and two SATA drives.
(Adaptec 48300 controller) So far it's working fine. I'll post back here
if they disassemble themselves from the 'vibrations' . . . .

John L Rice