# Please Advise:Gentoo and user friendly SATA and SATA raid

## phil_at_nhs

Need a card for a basic file server.  What are the good ones to work with Gentoo on a standard PC format?

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## NeddySeagoon

phil_at_nhs,

Why not try kernel raid with the on board HDD controllers before spending money on a card.

A hardware raid card will be over £100 and a BIOS software raid card (e.g. SATA card) is not the way to go for a pure linux system.

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## phant0ml0rd

If you want just SATA capabilities use something like the Promise TX4. It costs ~ $55 and has 4 sata ports. It has good support and works out of the box (assuming the kernel support has been compiled). As far as RAID goes, if you are not willing to spend $300-400, just go with software raid in the kernel. The performance penalty is minor.

HTH

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## phil_at_nhs

Hey Neddy,

The machine in question has no onboard SATA.

PhantomLord, 

Thanx.  This is why I asked for both SATA and SATA RAID, I was thinking of going the software route.  I won't be installing into the raid, it will just be for Data, and basic performance will not be a huge issue for this application.

Promise TX4 was one of the optoins I was looking at...

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## NeddySeagoon

phil_at_nhs,

I suspected as much. You do not need SATA to do raid. Its faster with IDE if you only have one drive per channel but kernel raid still works with IDE. If you have the bits for a performance test, give it it try.

Note that kernel raid raids partitions not whole drives, so you don't even need identical drives. You can use the leftovers unraided. 

What raid level do you want ?

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## Cyker

 *phil_at_nhs wrote:*   

> Need a card for a basic file server.  What are the good ones to work with Gentoo on a standard PC format?

 

Unless you REALLY REALLY need a hardware RAID card (And I'm thinking you probably don't since you said you want a basic fileserve...  :Wink: ), you're better off spending the money on a decent mobo with lots of SATA ports.

I was looking at 4x PCIe SATA RAID cards, but most of them were 'accelerated' RAID (i.e. crap), or cost over £200.

In the end, I upgraded the motherboard to one that had 5+1 SATA sockets - it cost me less than both the hardware RAID card or the 'accelerated' RAID card, and I get 2 PCIe-connected gigabit ethernet connectors to boot  :Very Happy: 

(On a Tangent, does anyone know of any 4/6/8 port SATAII PCIe cards? Most of what I could find were PCI or PCI-X. The only PCIe ones I found were the expensive hardware RAID sort...  :Sad: )

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## phil_at_nhs

Neddy, I will probably be running 3 500 gig drives in a Raid 5 configuration.  I am going SATA mostly because I can get 500 gig SATA drives pretty dang cheap.  

Cyker, I am using an existing system for this, so hope to avoid the hassle of a motherboardectomy, plus, my cheapest solution appears to be just a 4 port SATA card.

Thanxs all for the advice.

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## NeddySeagoon

phil_at_nhs,

Almost any 4 port SATA card will do you but you will find that your raid data bandwidth will be choked by the PCI bus,

so you will be disappointed by the performace.

You get at most, 133Mb/sec on the bus. As a file sever, the data must pass over the bus twice. Raid to memory, memory to network card. In a 3 disk raid 5, you have to write data to three drives, so there is overhead there.

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## phant0ml0rd

PCI is 133 MB(as in Bytes not bits) per second :) This translates to 1063Mbps . This means that under ideal conditions, you wont be saturating even a 1Gbps ethernet link. So for file sharing purposes you should be fine.

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## Cyker

It does depend on what else is using the PCI bus 'tho.

Luckily, most mobos use something like HyperTransport for most mobo-comms and the PCI bus is relegated to just expansion cards.

Still, assuming you have any PCIe slots, I'd recommend a PCIe one if a) You can find one and b) It's not too expensive.

A single PCIe slot has more capacity than the entire PCI bus and, unlike the PCI bus it doesn't have to share  :Smile: 

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## phil_at_nhs

I am kinda stuck with what I have.  This will not be used for any applications, just spreadsheets and word docs and such, so performance will not be a huge deal.

I just received my drives and card, (promise 300 TX4 ) and am  little confused about setting it up, so look for a post on that subject.  Thanx all for al the advice.

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## hitman_bond007

I'm about to buy the TX4 and 3 SATA drives to put in a kernel RAID 5. Since this is very similar to your setup, I'm curious about how well it performs and what the rest of your hardware is.

I would like to try putting this in a Pentium 3 450 MHz machine. Does anyone know how well this would perform? Can this CPU handle the computation of RAID 5 without being a bottleneck? If this machine can't handle it, I'll just have to use my Pentium 4 1.8 GHz machine instead.

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## phil_at_nhs

Hey Hitman,

I am trying to get this up and running an a generic 2.8 gigahertz Pentium Box, with a gig of RAM.  I am using Western Digital Drives. But I am having a problem.

Following the Instructions in the Howto, 

http://gentoo-wiki.com/HOWTO_Gentoo_Install_on_Software_RAID#Misc_RAID_stuff

You get to this set of commands:

mdadm --create --verbose /dev/md1 --level=1 --raid-devices=2 /dev/sda1 /dev/sdb1

mdadm --create --verbose /dev/md2 --level=1 --raid-devices=2 /dev/sda2 /dev/sdb2

mdadm --create --verbose /dev/md3 --level=1 --raid-devices=2 /dev/sda3 /dev/sdb3

mdadm --create --verbose /dev/md4 --level=1 --raid-devices=2 /dev/sda4 /dev/sdb4

This takes the partitions on separate drives, and arrays them together.  The first one works fine, but the second gives me an error, which  posted on it's own thread.  No useful response yet.

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