[CentOS] SELinux threads, cynicism, one-upmanship, etc.

Bryan J. Smith thebs413 at earthlink.net
Thu Nov 17 18:11:30 UTC 2005


Will McDonald <wmcdonald at gmail.com> wrote:
> I've had no problems hot-swapping SATA drives on 3Ware
> 8006-2LP controllers

That's because the 3Ware controller is a _true_ hardware
RAID.
The _physical_ hardware is never seen by the kernel -- it's
not some logical organization, but _physical_.

The kernel only talks to the ASIC.  The ASIC talks to the
disks.  The kernel _never_ talks to the disks.

"FRAID" cards just hide the disks in software.  The kernel
still very much sees the "raw" ATA channels.  That's why you
need hotplug for FRAID.

But not for 3Ware.

> You can "park" the disks in 3warecli, swap them out and
> then rescan for new disks[1].

That's because you're commanding the ASIC to do this, and the
geometry of the volume _never_ changes from the standpoint of
the  kernel from a _physical_ (i.e., electrical) standpoint.

> The drive caddys are a bit "boy-racer" and not as solid as
> good SCA caddys from say Compaq or Dell but they do the
job.

SATA is staggered connectors for power, if you're using it in
it's native connector mode (no Molex).


-- 
Bryan J. Smith                | Sent from Yahoo Mail
mailto:b.j.smith at ieee.org     |  (please excuse any
http://thebs413.blogspot.com/ |   missing headers)



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