Maybe you should re-post that in success stories or something with the title of software raid howto or something(search-wise it'd help everyone right?)...because I came into this thread looking for hardware raid explanation :-/

That does sound very usefull however...and cheaper.

I have a question though, for raid 0 Can you make a swap partition accross the discs along with the / partition or is that unwise?

Since this is titled hardware raid may I ask some hardware raid questions?

http://www.ajump.com/ajump/product.a...2D99%2D4240148

Is the board I'm thinking of getting because mine's horrid and since it has hardware raid I'd like to use it (along with software for my ata drives)

The before said board has 2 SATA ports onboard that can use raid 0 or 1 can I use pci cards to add more than two drives to the array? Will the drives hooked into the controller cards write and read slower, thus slowing all the drives down(in raid0)?

Do you set up raid on hardware through bios?

Do the drives have to be identical in hardware raid?

I read up on SATA drives and the artical said they are only 5% faster the ata drives because they cannot use the higher speeds right now. Can they run faster in linux because of support or anything?

Okay, so the last one wasn't so much a raid question...

thanks for any help

Swap will use whatever device is most avialable, so no - don't try to do swap over software RAID. You could just have a swap partition on each drive and the kernel will manage it best. As for hardware RAID... I guess, but If you're tying into a lot of swap space I'd recommend more RAM. Lots.

Tough question. Short answer is possible, but you would be exposing yourself to some problems due to the schema. You'll have two SATA drives running RAID0 and then two ATA drives also running RAID0. You could use these to create a RAID0+1 array but personally I'd be uncomfortable with the mixing of controllers and such. Come to think of it I'm not even sure if you could use the SATA RAID device as a member of another software array.
The RAID controller cards usually come with a BIOS array management utility accessible after the normal POST/boot sequence. Some arrays have additional management software but it is primarily Win32 based
Nope, but the arrays will be built to accomodate the smallest member of the array and run at the limit of the slowest member.
A single drive is not much faster, but since the parent channel can handle a huge load of data the theory goes that more drives could equal better performance (at least in a non-redundant RAID0 configuration)
So I turned it into one.
No prob.

An update on the Trinity rig that I used in the afformentioned post - I made some changes and had to pump 50GB back onto the array from a single drive. I had an overall average write speed of 15.7MB/second (Around 48GB of data copied with plain old cp -pr in 52 minutes) . Keep in mind that I'm only using ATA/66 controllers, but I think that's pretty impressive

[edits: a bajillionkajillion typos. My keyboard acts funny after around 2am ]

Thank you so much. I wrote the onboard+pci sata controller question wrong yet you still give me an answer
Also, thank you for proving my pc hardware teacher wrong in just about every aspect of raid .

Sorry to dig up such an ancient post, but I'm in much the same boat (four years later) with virtually the same equipment as described in mcleodnine's "recent example."

I'd like to make a backup repository for household/family uses (basically something to copy /home and My Documents dirs regularly, maybe remotely) on a home server. I have few bones about performance or uptime; this is completely low-budget personal usage.

I found that Promise (PDC20262) card on a system I'm turning into a server, and it's old, but it has never been used. I'm somewhat confused by this thread, but using the Promise card for a RAID would be a hardware or software method?

And if the Promise card suddenly fails after I set up a RAID with it, can I pop in another or how do I get my RAID back up?

Has anything new come up with this issue? According to the Promise Tech documentation I dug up, the card (I only have one) supports up to four drive (each pair, M/S). If I have no bones about performance, just the backup, is it OK to put more than two HDs on a card with 2 IDE channels?

I love playing with dmraid, but in your case, since the card is limited to UDMA4 (66MB/s) I'd recommend that you go with mdadm. That will allow you to move the drives to a faster controller without trauma. With dmraid, you'd pretty much be stuck on that card.

The mdadm package is a bit confusing at first, but install it on your Linux system, study the man pages, look through the web and hear, and then try to create a RAID using your devices. If you run into trouble I'll give you a hand.

OTOH, if you're just looking for a way to backup documents, etc, get a DVD-R drive and plop your stuff on that periodically.

The promise cards are software RAID. They are little more than a shell to plug drives into.

For home use it isn't bad, it just isn't nearly as good as hardware RAID. The difference is easily expressed as what handles the RAID function. If the OS does it, it is software RAID. If there is a specific piece of hardware (not your mobo) that is there just to do RAID, then it is hardware.

Regardless of how your physical setup goes, you very much want to use the greatest piece of perl on sourceforge, backuppc. It is a great piece of software that is configurable to backup many machines in different ways. For doing LAN backups, you'll have the best time with rsyncd in my opinion, but see for yourself.

http://backuppc.sourceforge.net

Peace,
JimBass

"The promise cards are software RAID. They are little more than a shell to plug drives into. "

Well, the promise cards do allow you to create an array that's bootable by both Windows and Linux, but other than that, yes, they're just cards as far as Linux is concerned. A big problem with the FastTrak66 is that it's slooooowwww by modern standards. If the motherboard has a supported SATA controller, it would be MUCH better to put a big SATA drive on it, than to play with the Promise card. Barring that, if the native IDE controller is UDMA/133, then that would be much better to use (with a big drive) as well.

Promise controllers are not reliable and stable under Linux. I suggest buy a few Highpoint Rocket 100/133 because they are very reliable and stable under Linux.

UDMA-2 is good enough for 100 Mb networks. The transfer rate for hard drives ranges from a few kilobytes to 30 MB per second. This is after including the filesystem. It really does not matter what DMA level it is set at because RAID-0 or RAID-5 will eventually improve its write and read transfer rates. Also LVM2 and EVMS can also improve transfer rates because they try to do stripping when possible.

For software RAID, I suggest putting the hard drive on a separate controller. By doing this, a fail drive can bring down a controller with out effecting other hard drives.

Though you still have to think about backups even though your setup is software RAID. Hitachi has a 1 TB hard drive that is going to be selling around $400. That drive is cheaper than creating a terabyte array. You could buy a USB/IEEE-1394 (aka Firewire and i.Link) external enclosure that can handle a terabyte hard drive.

"Promise controllers are not reliable and stable under Linux."

How so? What problems can I expect? I've been running 2 RAID0s on this FastTrak66 test mule for several weeks and I can't say that I see anything obviously unstable or unreliable.

Added:
You're not thinking about the RAID driver Promise released for 2.4 are you? That's not used with 2.6 and dmraid. But, I will agree that if the metadata gets buggered, it is a bitch to straighten out.

Thanks to JimBass for clearing up the hardware/software Promise question for me. And thanks for the backuppc link. I was thinking of some rsync setup, but I'd also like to do backups over the internet, so that, say, my mother can click a button on her Windows desktop and schedule a backup of all her photos overnight. backuppc looks like what I want.

And thanks to Quakeboy02 for the mdadm tip. Sounds likes you're doing with your test mule what I'm hoping to do.

As far as the Promise controller goes, I wouldn't use it bootable, only as a backup repository -- the home server (and its other services) will be running off a disk on the regular IDE bus. So I'm OK with the card being slow, so long as it lets me put enough disks in the box and works.

Are there any good new-to-RAID resources for Linux software RAID besides the Software-RAID HOWTO (v1.1, 2004-06-03) that I should be googling?

Because I wonder how difficult is it to add new disks later to increase capacity to a software RAID/Promise array via, maybe, a spare IDE bus or on PCI IDE controllers; or if the Promise card should fail and I have to find some other physical arrangement for the disks, is it reasonably possible to reconfigure the software RAID to pick up and put back together the the pieces?

If you use mdadm, then you shouldn't have any worries about moving the array to another controller if the Promise goes bad. You can do a search here on LQ for mdadm. Here are some other sites I've found, as well. It's not hard to use, but it's intimidating at first. Just play with it and you'll figure out how it goes.

http://www.linuxdevcenter.com/pub/a/...2/05/RAID.html

http://www.networknewz.com/networkne...anagement.html

Don't forget to look at the man pages, as well.

Cool, thanks for the tips.