Re: [gentoo-user] [OT] 3ware SATA Raid

[Boyd Stephen Smith Jr.]

On Friday 10 February 2006 12:39, Rick van Hattem <Rick.van.Hattem@××××.nl> 
wrote about 'Re: [gentoo-user] [OT] 3ware SATA Raid':
> On Friday 10 February 2006 10:14, Etaoin Shrdlu wrote:
> > So, I'm finally going to buy a 3ware 9550sx SATA Raid board.
> >
> > From what I've read, it is well supported by linux and it should do
> > true hardware raid (ie, the OS sees only one drive). Anyway, I found
> > little documentation about the so-called hot-swap feature.
> > As I understand it, that means one should be able to remove a faulty
> > disk from the array, and subsequently insert a new disk, all without
> > powering off the machine, and with the OS being unaware of what's
> > going on. Is my understanding correct or am I too optimistic?
>
> You are correct, you are able to hot-swap the drives without rebooting
> or anything.
>
> But...... Areca cards are a lot faster for the serial ata stuff, altough
> I'm not sure about there linux driver support, it's worth to take a look
> at there stuff :)

They have supported drivers (GPL'd, IIRC) that go back to 2.3.x kernels.  
2.6.16 might include them in mainline, mm-sources has included them since 
2.6.14, at least.  I think RHEL4 will include the drivers in their kernel.

They also provide 32- and 64-bit command line utilities that can do all the 
controller operations from within linux, as well as both 32- and 64-bit 
http servers that will run on the machine with the controller and provide 
a remote (or local) management console that provides all the controller 
operations.  If you want to integrate the controller management into a 
larger tool, or write a gtk/qt frontend, they publish the public API 
provided by their closed source, but freely available arecalib.

Areca cards do handle the hot-swap feature mentioned by the OP.  
Unfortunately (and from what I've read this is a limitation of linux...), 
newly created arrays or pass-though drives do not immediately appear 
in /dev nor do removed arrays or pass-through drives disappear.  That 
said, the scenario given by the OP (replacing a faulty disk live) does not 
add or remove device node in /dev so it will work perfectly.

I love my Areca 1160.  There's only one feature I wish it handled that it 
doesn't: the non-standard RAID 1n, which is RAID 1 (mirroring) with more 
than 2 drives in the array -- something that should've been trivial for 
them to implement.  So, instead I use RAID 6, which is fairly nice.

-- 
Boyd Stephen Smith Jr.
bss03@××××××××××.com
ICQ: 514984 YM/AIM: DaTwinkDaddy
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