[Gllug] Hardware IDE RAID

[Doug Winter]

On Sat 17 Jan Simon Faulkner wrote:
> Does it need software drivers or does it do all it's work in hardware?

It's completely hardware - the pair of disks appears as a single scsi
drive to the kernel:

SCSI subsystem driver Revision: 1.00
3ware Storage Controller device driver for Linux v1.02.00.036.
scsi0 : Found a 3ware Storage Controller at 0xb800, IRQ: 24, P-chip: 1.3
scsi0 : 3ware Storage Controller
blk: queue c1cc9a18, I/O limit 4095Mb (mask 0xffffffff)
  Vendor: 3ware     Model: Logical Disk 0    Rev: 1.0
  Type:   Direct-Access                      ANSI SCSI revision: 00
blk: queue c1cc9818, I/O limit 4095Mb (mask 0xffffffff)
Attached scsi disk sda at scsi0, channel 0, id 0, lun 0
SCSI device sda: 398295040 512-byte hdwr sectors (203927 MB)
Partition check:
 /dev/scsi/host0/bus0/target0/lun0: p1 p2 p3 p4 < p5 p6 p7 p8 p9 >

sda here is really two IDE disks.  There is a configuration utility that
is accessible at boot time which allows you to configure the mirror, and
they provide a daemon, 3dmd, that monitors the status of the RAID,
emailing you if part of it breaks, and allowing you to rebuild the raid
if a disk fails.  

Irritatingly it's accessed over the web, but it works in text-based
browsers.  It generally looks something like this:

  SCSI ID 0  3ware 7006-2 ATA RAID Controller
    * Array Unit 0  Mirror (RAID 1)  203.92 GB   OK
         + Port 0 Maxtor 6Y200P0    203.92 GB   OK
         + Port 1 Maxtor 6Y200P0    203.92 GB   OK

Aha - actually you want the 7006-2, for some reason all the other
escalades are 7506-something, but the 2 drive one isn't :)

http://www.3ware.com/products/parallel_ata.asp

The 3ware driver is part of the kernel (CONFIG_BLK_DEV_3W_XXXX_RAID),
and is compiled as a module in Debian stock kernels - No idea about
other distros though.

doug.

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