Assistance needed for HW Raid1

[dude67]

I recently had my main PC crash (some 18 mo old hw) and I suspect it had to do with HDD giving in. I at first lost /home partition and after re-installing Mandriva 2008.1 (Free, from DVD) it wouldn't fire-up the second time as it said that I missed root partition... The system was a dual boot with WinXP Home. The XP started OK, but I still suspected a dying HDD (Seagate Barracuda 500GB 7200.10 SATA)

 

I didn't have the patience to dig any deeper, so went to the local computer store and bought me a set of two 750GB Samsung HDDs. I thought I confirmed that my MB would support RAID, but it turned out it didn't... (I read some manual on the net, that turned out to be a manual of a similar but not the same MB). The motherboard is MSI 945P NEO3-F.

 

OK, so now I have two nice 750GB disks that I want to make into RAID1 array with the system that has WinXP Home (some 200GB for that) and Mandriva (the rest: 550GB).

 

I was thinking of buying a RAID controller card (since I don't want to install the whole PC anew with a new MB) and wanted to ask you if there's anything I need to know before buying one. As Ian said here, there are sw RAIDs and hw RAIDs; are the both types available for PCI RAID cards also? I would like to go with hw RAID as it's said to be more reliable.

 

Here are some of the PCI cards I found with my local PC dealer.

• Innovision DM-8301R at 35€
  
• Adaptec 1210SA at 75€
  
• Promise at 79€
  
• Dawicontrol DC-150 at 65€
  
• Dawicontrol DC-154 at 55€
  

I'm totally new to making any disk arrays so your advice is greatly appreciated.

Edited August 26, 2008 by dude67

[ianw1974]

I've just bought an Adaptec 1430SA SATA 2 raid controller but of course you can use this for sata 1 disks too. It supports Raid 0, 1 and 10. I've also bought 4 x 250GB hard disks with 32mb cache :)

 

I prefer Adaptec to any others, alternatively, find one with a MPT Fusion chipset (LSI Logic/Symbios Logic SAS1068) as these are supported by default in kernels without any additional modules required. The Adaptec's if not default supported in kernel will only be supported by modules released by Adaptec, and therefore you tend to find yourself limited to Red Hat/CentOS or SUSE Linux. Of course, you can download and compile the source. Incidently, usually if you don't have the module, then it just sees 2 x hard disks or whatever installed, meaning it has just ignored the raid array you configured on the card.

 

Bear this in mind, if you go with Adaptec, else hunt out a card like I mentioned. Here is one I have installed with Raid 1.

 

02:08.0 SCSI storage controller: LSI Logic / Symbios Logic SAS1068 PCI-X Fusion-MPT SAS (rev 01)
	Subsystem: Dell PowerEdge 860 SAS 5i/R
	Flags: bus master, 66MHz, medium devsel, latency 72, IRQ 16
	I/O ports at ec00 [disabled] [size=256]
	Memory at fe9fc000 (64-bit, non-prefetchable) [size=16K]
	Memory at fe9e0000 (64-bit, non-prefetchable) [size=64K]
	Expansion ROM at fea00000 [disabled] [size=1M]
	Capabilities: [50] Power Management version 2
	Capabilities: [98] Message Signalled Interrupts: Mask- 64bit+ Queue=0/0 Enable-
	Capabilities: [68] PCI-X non-bridge device
	Capabilities: [b0] MSI-X: Enable- Mask- TabSize=1
	Kernel driver in use: mptsas

 

this card I really like, and it's not that expensive. I got it when I bought a Dell PowerEdge 840 server and Dell supplied it hence the subsystem info on it. But you can buy them separate, and the price is good too. Check slot support to see what's available on your motherboard. The Adaptec I have is PCI Express, whereas this SAS1068 is PCI-X in the server but can be used in any machine, including desktop.

[paul]

I'm big on 2ware cards, but they tend to be expensive

 

I also use a bunch of MPT stuff in my dells .. good stuff

[dude67]

OK, now you got me a little confused... As I did admit, I know very little of making a Raid array, so a few questions.

 

If I understood Ian's point correctly, the Adaptec cards tend to work out-of-the-box only with Red Hat/CentOS or SUSE Linux (and with windows). Unless I would compile from source (I would definitely need some assistance there...).

 

I called my local store and this is what they have on shelf:

• Promise SATA300 TX2plus (data sheet)
  
• Adaptec 1210SA (tech info on this page)
  

When I look at the data for these two cards, I would seem that they only promise RH/CentOS and SUSE.

 

And if I again understood correctly, the PCI-x slot is usually only in server HW; is that correct? I believe my MB has one PCI-e (used for my NVidia) and the rest are plain PCI. Here are the specs for my MB: http://global.msi.com.tw/index.php?func=pr...p;cat3_no=#menu

 

I seem to be no closer to fixing this. When I look at the two cards that seem available at the local store, I don't know if either of them is what I'm looking for.

 

Oh, one thing: If I connect the two HDDs to the RAID controller and that controller card is connected to regular PCI slot, will that slow the computer down (compared to being connected directly to the MB via SATA)?

[dude67]

I could change my MB to a one that supports RAID.

 

That, and I could give Ian's software raid installation walk-through a go...

[ianw1974]

Compiling from source will be a little difficult if you're trying to get an OS installed on the machine to access the disks. However, if you had a disk in the system already active but not attached to the Raid Controller, then you would have an active system to then compile the module into the kernel to access.

 

You'd then effectively have 3 disks in the system. One for the main system to get it installed, and then the 2 x Raid 1 mirror to be accessed for data for /home for example. Otherwise, you're limited to the distros mentioned for the particular cards unless it's natively supported in the Linux kernel - which for some cards are. Sometimes the Promise ones are, but it would require checking to make sure.

 

This is why I recommended the LSI Logic/Symbios Logic chipsets, as they are usually very easy to check if there is support in the kernel. It's more the chipset info we need on the cards, to be able to dig further for kernel support.

 

However, on just checking the kernel 2.6.24.x which I've just checked on my Gentoo system, does have support for the Promise card you listed above. Here is the info:

 

Promise SATA TX2/TX4 support

 

will compile a module called sata_promise into the kernel. Unless of course it's compiled monolithic, then it'll be inside the kernel, rather than a module. Whichever distro you're using, you can check my simply modprobing the sata_promise module and then check with lsmod to see if it's listed. Alternatively, check with lsmod first, as it might already be loaded by default.

 

I don't know what earliest kernel supports this, but you can check depending on what's installed on your system.

[ianw1974]

I could change my MB to a one that supports RAID.

 

That, and I could give Ian's software raid installation walk-through a go...

 

You only need software raid if your motherboard doesn't support raid or that you have a card to do it. If you have a card to do it, then you don't need the software raid tutorial. On the other hand, if you remove the two disks with software raid from your system, you can put them in another Linux machine with mdadm installed and then re-activate the array and access your data.

[dude67]

However, on just checking the kernel 2.6.24.x which I've just checked on my Gentoo system, does have support for the Promise card you listed above. Here is the info:

 

Promise SATA TX2/TX4 support

 

will compile a module called sata_promise into the kernel. Unless of course it's compiled monolithic, then it'll be inside the kernel, rather than a module. Whichever distro you're using, you can check my simply modprobing the sata_promise module and then check with lsmod to see if it's listed. Alternatively, check with lsmod first, as it might already be loaded by default.

 

I don't know what earliest kernel supports this, but you can check depending on what's installed on your system.

I'm not currently at home, but does anyone know, what's the current kernel version with mandriva? Is it above the kernel 2.6.24.x that Ian mentioned?

 

So if I (again) understood correctly, it would seem that the promise card has a better chance of working with mandriva?

 

Anyway, how would I start the installation of the RAID1 array? I just yesterday installed WinXP home on the first drive (on the first 250 GB) and the rest (some 500 GB of the first HDD and the other HDD completely unformated) is just "sitting there".

 

I don't mind if I need to install the windows xp again - but if I get the Promise card, I would install this in to the PCI slot and connect the two HDDs into the card's SATA connectors. What then? I don't need to flash the BIOS or anythign? I will most likely need to install Windows XP again and then proceed with installing Mandriva. But when and how do I install/configure the RAID1 bit? The card will come with a manual, I hope...

[dude67]

You only need software raid if your motherboard doesn't support raid or that you have a card to do it. If you have a card to do it, then you don't need the software raid tutorial.

That's understood. I was just thinking out loud wondering what other choises I have besides the RAID controller card.

 

Very detailed instructions for the SW RAID - nice work, Ian!

[ianw1974]

If you use a hardware raid controller, you'll be able to press a key sequence to then go into the raid controller's bios and configure the raid 1 array. Then, you'll basically find when you boot your system, you'll only see one disk. If you see two, then a generic sata driver is being used and not the one for your raid controller. I had this once with a card that didn't have a supported module in the kernel (Adaptec 1430SA to be exact). Anyway, once I had the correct module, I saw only one disk, and therefore all meant the controller was being seen correctly, and the raid was working.

 

I believe Mandriva is 2.6.24 already, but you can get the kernel-linus-latest I think and it will be bang up to date kernel.

 

Using hardware raid, yes you'll need to reinstall Windows again later :)

[dude67]

OK, thanks Ian.

 

But I currently have no linux kernel installed as I currently have only WinXP. And after I install the RAID1, I'll first re-install Windows and only then install Mandriva. Should I not already have the RAID1 array operating at that time? Or do you mean that by the time I come to install Mandriva and the linux kernel, I may have trouble when rebooting in RAID1 mode?

 

Anyway, I'll pick up the Promise card on my way home soon. I'll post back my progress, whenever I have an operable system running - either from windows or from Mandriva.

 

(Sorry for the very noob questions... :P Hope you bear with me awhile. )

[ianw1974]

The Raid 1 array will be operating because you configured it on the Raid Controller card when you booted and pressed the hot-key to get into the Raid BIOS to configure it :)

 

Then you'll install Windows followed by Mandriva. I confirm that my install of Mandriva 2008 has 2.6.24.x kernel by default.

[dude67]

...my install of Mandriva 2008 has ...

but your sig doesn't say you have Mandy installed...! :deal:

 

[ianw1974]

It's in VMware ;)

[dude67]

This is getting absurd... I went and bought the card. But you know what; it isn't a RAID controller - even though I asked for one.

 

I'm going to take it back to the store tomorrow. I just don't know what to do as the only other card they have available (other types are on order) is the Adaptec. But if the Adaptec one doesn't work out-of-the-box in Mandriva, I don't want that one.

 

I may end up making the software raid of my system. But does that work with the whole disk as I also have Windows in it?