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

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

[Etaoin Shrdlu]

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?

More generally, what are your opinions/experiences with 3ware boards?

Thanks

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

[Rick van Hattem]

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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?
>
> More generally, what are your opinions/experiences with 3ware boards?
>
> Thanks

You are correct, you are able to hot-swap the drives without rebooting or 
anything.

I have a 3ware 7506-12 card and I'm able to hot-swap drives aswell, the 
drivers work very good and the management tool allows you to 
create/modify/rebuild raid arrays without rebooting.

My opinion, 3ware is a great brand with great cards and I'd definately 
recommend them.

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 :)

-- 
Rick van Hattem	Rick.van.Hattem(at)Fawo.nl

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

[Boyd Stephen Smith Jr.]

On Friday 10 February 2006 12:39, Rick van Hattem <Rick.van.Hattem@fawo.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@volumehost.com
ICQ: 514984 YM/AIM: DaTwinkDaddy
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Re: [gentoo-user] [OT] 3ware SATA Raid

[Etaoin Shrdlu]

First of all, thanks for your answer.

On Friday 10 February 2006 19:39, Rick van Hattem wrote:

> You are correct, you are able to hot-swap the drives without rebooting
> or anything.
>
> I have a 3ware 7506-12 card and I'm able to hot-swap drives aswell,
> the drivers work very good and the management tool allows you to
> create/modify/rebuild raid arrays without rebooting.

But how do you actually hot-swap the drives? Does the disk that is going 
to be removed have to be somehow powered off (eg, via some switch in the 
backplane or in the enclosure) before? (Sorry for the dumb questions, I 
read a reasonable amount of documents about RAID but actually I never 
had to deal with it in the real life - until now of course).

Is the management tool opensource or is it a binary proprietary program?

> 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 :)

Well, areca is in fact the other brand I was interested in (together with 
LSI)...I'm not sure, but they seem to use marvell chipset; there is 
support for it in the kernel, although the driver is still experimental 
(but they mantain a separate opensource driver). Don't know about their 
management tools (infos are welcome).
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Re: [gentoo-user] [OT] 3ware SATA Raid

[Jarry]

Etaoin Shrdlu wrote:

> But how do you actually hot-swap the drives? Does the disk that is going 
> to be removed have to be somehow powered off (eg, via some switch in the 
> backplane or in the enclosure) before? 

I think hot-swap is supported by sata itself (I mean hardware side), similar
as for usb: grounding pins are longer, i.e. you can just simply pull out
power-cable and then data-cable even while your server is on. Or you can
buy special swappable enclosures for sata-disk, which is mounted in free
external 5 1/4" position (e.g. from ViPowER SwapRack) and easily pull out
sata disk from your server...

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

[brettholcomb]

Most hot swap stuff has the drives in caddys that fit in a mount.  The mount contains power connections and drive connections.  the caddy has cables for the disk data and power that go to a connector on the caddy. The caddy slides into the mount and the connections are made.  Some caddies have a lock on the front that cuts off power when unlocked for removal.

> 
> From: Etaoin Shrdlu <shrdlu@unlimitedmail.org>
> Date: 2006/02/10 Fri PM 02:50:24 EST
> To: gentoo-user@lists.gentoo.org
> Subject: Re: [gentoo-user] [OT] 3ware SATA Raid
> 
> First of all, thanks for your answer.
> 
> On Friday 10 February 2006 19:39, Rick van Hattem wrote:
> 
> > You are correct, you are able to hot-swap the drives without rebooting
> > or anything.
> >
> > I have a 3ware 7506-12 card and I'm able to hot-swap drives aswell,
> > the drivers work very good and the management tool allows you to
> > create/modify/rebuild raid arrays without rebooting.
> 
> But how do you actually hot-swap the drives? Does the disk that is going 
> to be removed have to be somehow powered off (eg, via some switch in the 
> backplane or in the enclosure) before? (Sorry for the dumb questions, I 
> read a reasonable amount of documents about RAID but actually I never 
> had to deal with it in the real life - until now of course).
> 
> Is the management tool opensource or is it a binary proprietary program?
> 
> > 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 :)
> 
> Well, areca is in fact the other brand I was interested in (together with 
> LSI)...I'm not sure, but they seem to use marvell chipset; there is 
> support for it in the kernel, although the driver is still experimental 
> (but they mantain a separate opensource driver). Don't know about their 
> management tools (infos are welcome).
> -- 
> gentoo-user@gentoo.org mailing list
> 
> 

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

[Etaoin Shrdlu]

On Friday 10 February 2006 20:34, Boyd Stephen Smith Jr. wrote:

> 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 
> [cut]

Well, thanks for the valuable info. I should really rethink about my 
choice and reconsider areca.
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Re: [gentoo-user] [OT] 3ware SATA Raid

[Etaoin Shrdlu]

On Friday 10 February 2006 22:04, brettholcomb@bellsouth.net wrote:

> Most hot swap stuff has the drives in caddys that fit in a mount.  The
> mount contains power connections and drive connections.  the caddy has
> cables for the disk data and power that go to a connector on the
> caddy. The caddy slides into the mount and the connections are made. 
> Some caddies have a lock on the front that cuts off power when
> unlocked for removal.

Ok, thanks to everybody for your helpful replies.
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