CentOS - May 2005 - Hardware RAID Controller

Hi Everyone,

Has anyone had any experience of using the Promise FastTrak SX4000 or 
SuperTrak SX6000 IDE RAID Controllers under Centos  (if it matters I'm 
using version 4). I've seen it listed on linuxcompatible.org as working 
but would prefer to find out any first-hand experince before I buy.

I'm looking to build a new mini server based on Mini-ITX and have found 
a great 1U case that support upto 4 IDE drives.  It would be good to 
muck around with hardware RAID.

If not, can anyone suggest another make of RAID Controller that will 
support upto 4 IDE RAIDS (preferably with support for RAID 5). And is 
also available in the UK.

Thanks in advance.

Regards

Lee

Lee W wrote:
> Hi Everyone,
>
> Has anyone had any experience of using the Promise FastTrak SX4000 or 
> SuperTrak SX6000 IDE RAID Controllers under Centos  (if it matters I'm 
> using version 4). I've seen it listed on linuxcompatible.org as 
> working but would prefer to find out any first-hand experince before I 
> buy.
>
> I'm looking to build a new mini server based on Mini-ITX and have 
> found a great 1U case that support upto 4 IDE drives.  It would be 
> good to muck around with hardware RAID.
>
> If not, can anyone suggest another make of RAID Controller that will 
> support upto 4 IDE RAIDS (preferably with support for RAID 5). And is 
> also available in the UK.
>
I don't have any experience with the Promise card, but I can highly 
recommend any recent vintage 3Ware RAID card.  They're not terribly 
expensive and the new 9500 4 port cards should be tiny enough to easily 
fit in a mini-ITX case.  That card plus 4 400gig drives would give you a 
4 disk RAID 5 array (with very good read/write performance) and well 
over a terabyte of usable storage.  It wasn't long ago that a 10gig 
drive was as big as a shoebox and now you can fit over a terabyte of 
redundant storage and a fairly powerful computer in the same form 
factor.  We live in interesting times. 

Cheers,

C

From: Lee W <centos-list at unassemble.co.uk>
> Has anyone had any experience of using the Promise FastTrak SX4000 or 
> SuperTrak SX6000 IDE RAID Controllers under Centos  (if it matters I'm 
> using version 4). I've seen it listed on linuxcompatible.org as working
> but would prefer to find out any first-hand experince before I buy.
Avoid the FastTraks.  Most are FRAID (Fake/Free RAID), 100% software with
0% GPL drivers.

The SuperTraks are a "true hardware" microcontroller+DRAM solution
with GPL
drivers.  Unfortunately, they use mega-yesteryear i960 microcontrollers not
able to keep up with today's drives.

When you want ATA and RAID-5, I recommend the LSI Logic with "x" in
the
product model to indicate XScale (superscalar StrongARM) microcontrollers.
> If not, can anyone suggest another make of RAID Controller that will 
> support upto 4 IDE RAIDS (preferably with support for RAID 5). And is 
> also available in the UK.
Is there any consideration driving RAID-5?
For a majority of applications, RAID-0+1 tends to be better.

I prefer 3Ware Escalade 7506/8506 series cards for RAID-0+1.
They use a 64-bit ASIC and SRAM (static RAM).

The 9500S series is still maturing, although they should eventually show
outstanding performance.
They add a large amount of DRAM to the existing ASIC+SRAM approach of the
earlier Escalades.



--
Bryan J. Smith   mailto:b.j.smith at ieee.org

Lee W wrote:
> Hi Everyone,
>
> Has anyone had any experience of using the Promise FastTrak SX4000 or 
> SuperTrak SX6000 IDE RAID Controllers under Centos  (if it matters I'm 
> using version 4). I've seen it listed on linuxcompatible.org as 
> working but would prefer to find out any first-hand experince before I 
> buy.
I've run the SX4000 under 3.4.  I have no experience with 4, but I 
wouldn't imagine support would roll backwards.
> I'm looking to build a new mini server based on Mini-ITX and have 
> found a great 1U case that support upto 4 IDE drives.  It would be 
> good to muck around with hardware RAID.
Go 3ware.  Promise is not a Linux friendly company, despite their 
attempts.  Their support guys have been downright rude to me on the 
phone in the past when I asked for updated drivers, telling me that 
"Linux is only X% of the market, blah blah blah".  I was ticked.  I 
stopped using them, and you should too.
> If not, can anyone suggest another make of RAID Controller that will 
> support upto 4 IDE RAIDS (preferably with support for RAID 5). And is 
> also available in the UK.
3ware.  Ebay.com is cheapest, but any vendor will do.  They're worth the 
money.  I've got over 5 TB of RAID on 3ware cards, with nary a failiure 
to date.

Jonathan
> Thanks in advance.
>
> Regards
>
> Lee
> _______________________________________________
> CentOS mailing list
> CentOS at centos.org
> http://lists.centos.org/mailman/listinfo/centos

From: Lee W <centos-list at unassemble.co.uk>
> Thanks for the heads up
See my (now dated) "Dissecting ATA RAID Options" article in SysAdmin
2004 April.
It covers 4 approaches to ATA RAID:
- OS LVM (software)
- FRAID (software)
- microcontroller+DRAM (hardware)
- ASIC+SRAM (hardware)
> No, just another toy to play with.  I'm currently looking a playing
with
> Software RAID but would like to have H/W as well.
The only time I implement RAID-5 is for lots of reads.
E.g., a MySQL server on the Internet.

I prefer RAID-0+1 for most operations -- definitely system disks.
RAID-3 is nice for desktop data and single user operations.**
RAID-4 is best for NFS server and large file transfer servers (A/V).

If I'm mega-anal on performance, I'll use multiple hardware RAID-0+1
cards on different PCI-X channels and volumes with a spanned RAID-0
LVM/LVM2 software volume across them.

I would kill to have a HP DL585 with (3) Escalade 8506 cards, one
on their own PCI-X channel, plus a 10GbE on the final PCI-X channel.

[ **NOTE:  For 32/64-bit I/O desktops, NetCell's 3 or 5-disc
"RAID-XL"
is actually the most ideal design I've ever seen.  Instead of striped
blocks, you have parallel reads/writes. ]
> I'm certainly liking what I have seen of the 3Ware card's so far.
Stock kernel support since version 2.2.15 (that's 2._2_ ;-).
It's nice to be able to move volumes from older cards to newer ones
without issue as well.
> Their site lists quite a few distros as supported, including RHEL 3 which
> from a simplistic guess would also mean that Centos 3 (and possibly 4)
> would also be supported.
Been using them in servers since Red Hat Linux 5.2.  The drivers for most
microcontroller or ASIC-driven hardware RAID are rather simplistic, because
all the "intelligence" is on-board the card itself.

3Ware's 3DM/3DM2 management suite is a nice addition, although there
have been some SCSI IOCTL changes that are rendering the older
Escalade 6000 as deprecated.




--
Bryan J. Smith   mailto:b.j.smith at ieee.org

From: Lee W <centos-list at unassemble.co.uk>
> Ebay UK didn't turn up much (althought there was a few in the US). 
> However just tried googling a bit more and I've come across a 3ware 
> Escalade 7506-4LP for about ???200.00 which supports upto 4 drives so that 
> should be suitable for my purposes, plus it looks quite small (being a 
> Low-Profile card) so should fit in the rack as well. 
You can even take the bracket off as long as you can mechanically secure
it another way.
> Okay I'm getting a bit over my head now.  Anyone see any problems 
> putting 2 of these in the same machine.
3Ware has always supported up to 4 cards in a system.
Just make sure the firmwares are the same for each model
or expect issues with drivers.
> After a few other comments I was thinking of trying 2 x RAID-1's.
Why not a 4-drive RAID-0+1?
It's far better to do it on a single card.

Unless you are thinking of (2) RAID-1, each on their own PCI-X channel,
and then a RAID-0 LVM2 stripe across them?

In reality, you're really gotta get up to 8 drives in RAID-0+1 before
you're going to saturate the 0.5GBps 64-bit @ 66MHz PCI bus.

And in all the 1U systems I've seen, I've only seen a maximum of (2)
PCI-X channels.  You'll want to use one dedicated to your NIC.



--
Bryan J. Smith   mailto:b.j.smith at ieee.org

centos-bounces at centos.org wrote on 10.05.2005 20:40:57:
> Has anyone had any experience of using the Promise FastTrak SX4000 or 
> SuperTrak SX6000 IDE RAID Controllers under Centos  (if it matters I'm 
> using version 4). I've seen it listed on linuxcompatible.org as working
> but would prefer to find out any first-hand experince before I buy.
Promise is crap with Linux in general, and they really don't support linux 
at all...

Like everyone else already said; go with 3ware or LSI.

Regards,
Harald
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From: Harald Finn???s <spamcatcher at lantrix.no>
> Promise is crap with Linux in general,
> and they really don't support linux at all...
Well, that's because 98% of Promise's products sold are FRAID (Fake/Free
RAID).
They are a "regular" ATA controller slapped with a 16-bit "trick
BIOS."
That system has the RAID code needed as long as OS is only accessing 16-bit BIOS
Int13h Disk Services.

The second a 32-bit OS loads, it sees the "raw" disks and doesn't
understand them.
That's where the 100% _software_ driver comes in, it emulates the volume for
the 32-bit OS.
Since all of that RAID code -- typically licensed from the same company by _all_
of the countless FRAID/mainboard-FRAID vendors out there -- it can't be GPL.

Hence why FRAID products don't have GPL drivers.
Except for the 'independent' GPL "ataraid.c" FRAID logic, and
the reverse engineered "hptraid.c", "pdcraid" and
"silraid.c" companion 'interface' GPL drivers.
Of course, there is *0* guarantee those non-vendor implementations will work.
I've seen people try to use them and toast their entire volume.

_Real_hardware_ RAID cards completely hide the disks from the system.
I.e., the system _never_ talks directly to the hard drives, but an intelligent
microcontroller or ASIC.
The "RAID Brains" is on the card, and the microcontroller or ASIC
actually executes that code -- not your main CPU.
The driver is then just a simple block driver to send data to/from the host
system to the on-board intelligence.

Hence why the drivers are typically GPL, there's little to them other than a
basic, block SCSI driver.
No RAID logic is ever exposed in the kernel driver.




--
Bryan J. Smith   mailto:b.j.smith at ieee.org

Ahhh, thanx for the insight.
I never liked their use of lackluster i960 33MHz and 66MHz parts.
You're lucky if you get 60MBps out of them.

-----Original Message-----
From: Harald Finn???s <spamcatcher at lantrix.no>
Sent: May 10, 2005 3:55 PM
To: CentOS mailing list <centos at centos.org>
Subject: Re: [CentOS] Hardware RAID Controller

centos-bounces at centos.org wrote on 10.05.2005 22:44:54:
> Well, that's because 98% of Promise's products sold are FRAID 
> (Fake/Free RAID).
The card I had in mind was the "real" RAID cards, i.e the SX6000. It
was
ok while RH8 was the standard and you didn't need to compile a new kernel 
(ie. you could use the Promise-supplied driver disks). They also had 
driver source for 2.4 which worked ok as long as you booted from another 
device and loaded the driver as a module.

And actually, the SX6000 worked with the I2O drivers for a little while 
with a patch supplied by Alan Cox, but after a few kernel updates I gave 
up on it.

I was in contact with Promise support about one year ago, and they told me 
that they had 2.6 drivers in beta, and that they would inform me when it 
became available. Needless to say, there's still no 2.6 drivers posted on 
their download pages.

Well, enough bitchin for now... :)

Regards,
Harald


--
Bryan J. Smith   mailto:b.j.smith at ieee.org

Lee W wrote
> However I've noticed that it is a 64-Bit PCI Card.  Can I still use
this
> in a 32-Bit Slot.  I think that I read something once that said it would 
> work but at a reduced bandwidth.
Joshua Baker-LePain wrote:
>Page 16 of the Installation Guide says a 32bit slot is fine.
From: Peter Farrow <peter at farrows.org>
> I use one of my 8500-8s in a 32bit slot on an MSI Dual PIII
> motherboard with no problems...
Two things of note:  

1)  66MHz capable cards

The "6" in 7506 and 8506 indicate it is 66MHz capable.
The 7500 (fka 7850) and 8500 are 33MHz capable, as are
all prior models.

All 7000/8000 series cards are 64-bit _except_ the
7000-2 (fka 7200) and 7006-2 (66MHz, but 32-bit).

2)  Multiple PCI/PCI-X busses

The most important consideration beyond bandwidth is the
PCI bus.  I have seen far too many people stick a 3Ware card
into a system that has a _single_ 32-bit at 33MHz PCI bus.

Back in the 1999-2001 timeframe, I made a buttload of money
just coming in and ripping out i440BX and i440GX mainboards
and putting in ServerWorks ServerSet IIILE/HE mainboards for
Pentium II/III systems.

3-4x performance is achievable by just getting the storage and
NIC on separate PCI (or PCI-X) busses.  Especially at today's
disk transfer rates and GbE on the same system.

[ SIDE NOTE:  A good GbE card with 256KB SRAM and using
9000 byte jumbo frames also helps. ]



--
Bryan J. Smith   mailto:b.j.smith at ieee.org