Brother, can you spare a couple of SCSI SCA disks?

[Tom Buskey]

On 10/22/07, Ben Scott <dragonhawk at gmail.com> wrote:
> On 10/22/07, Tom Buskey <tom at buskey.name> wrote:
> > The only place I'd seen SCA is on Sun boxes
>
>   Yah, we pee cee weenies have SCA too.  ;-)

As I should have said, I haven't looked into enough PCs :-)

> > Needs to be rack mounted then.
>
>   "Needs" is a strong word, but MV Communications has been generously
> hosting us for free, and the fact that it only takes up 1U in their
> racks is, I'm sure, making that easier for them to do.

Needs to look fairly decent and not take up lots of space.

>   Remember, in many datacenters, the most expensive commodity is
> space.  Not power, not bandwidth, but the physical space the machine
> takes up.
>
> > I've used the following which might be acceptable for GNHLUG or not ...
>
>   Well, the non-zero price tag and larger than 1U size might be an
> issue.  It's not that I've got anything against SATA, but we've got
> certain limitations due to what we're working with here.  The world is
> not your living room.  :-)

Well, the setup I described could be an old 1U server case stacked on top of
the current server.  Ways to mount the disks into the chassis are left to
the imagination.  Early Google internal servers, Nyx.com systems, etc might
be examples.  It doesn't have to look that ugly.

> > SATA is inherently hot plug.
>
>   But the drives won't be, without a hot plug backplane.  (How you
> gonna hook up those cables if the drives are stuffed into a 1U pizza
> box chassis with no room to spare?)

Let me try an ASCI drawing.. (sorry for going HTML mode to get courier)

          server                    Drive
SATA      case       SATA Cable     case       SATA
card -|-----|=   -|-------------|-   =|-----|- Disk
       SATA                            SATA
      extender                        extender


1) umount the disks
2) power off the drive case
3) unplug each the SATA cable from each SATA extender
4) swap out & repair
5) reverse 4 through 1

Your current server stays the same with the addition of a 4 port SATA card
and 4 SATA extenders from the card ports to the outside of the chassis
(label each cable with the port :-)

Your OS is on the 2 current SCA drives.  Your data is on the external SATA
disk in the other case.
Think of it like external SCSI drives everyone used to (still?) use with
much cheaper cables.  You could even use an old external SCSI drive case w/
1 disk, one extender.
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