Hardwae raid

[FatBastard]

Err now you're being hopeful. I bet the bottom dollar thay won''t work with all flavours of Linux.

IF the card gives a damn which flavour I'm running, then its a software - "Hardware Assisted" card.
a true HW card keeps all the raid and management stuff (Define arrays, rebuild , of swap etc...) in the card's on bios management app. The OS sees only a standard IDE/SATA/SCZ drive. anything other then that is not a true HW card.

That said, there should not be any issue running any card, which driver can be rebuild. the different Linux flavor is not as issue really, if you are willing to build a custom kernel.
there might be some cards out there which require a 2.2X or 2.4X or 2.6X kernel only, but I guess its pretty rare.

regardless, I am using CentOS 5 http://www.centos.org , which is a complete rebuild of RHEL 5, so I should be fine.

[Evildead666]

I was looking for a SATA Raid controller a while back, for video editing in RAW, and ended up using the onboard Raid in the intel Southbridge.
Asus P5WD2.

I use 4 disks, and it is very fast, and low CPU usage, but CPU is clocked so its more on stock CPU.

The price of the fully hardware raid cards made me come to my senses.
I just added another PCI based Sata card to boot from.

edit :For the Intel southbridge raid, its all done in the Raid Bios at POST level. <ctrl>+<I> and then I set it up for 4 disks.
XPpro just saw a new big 981Gb disk. I think it was formatted by the Bios application, largest block-size possible for me since very large files only.

There are No real Drivers for Windows at least...

[FatBastard]

On Intel boards, the <CTRL> + <I> brings up the Intel-Matrix-storage-chip's bios, AKA ICH7R RAID Technology. it is not a full hardware raid, as the OS driver does most of the work (in other words the system's CPU). there is no official Intel Linux support, but 3rd pretty drivers http://www.intel.com/support/chipset.../cs-020663.htm. I had no problem setting up my CentOS 5 to support it, but the kernel Panicked when I tried to boot without on of the disks in the array.

[Taz]

IF the card gives a damn which flavour I'm running, then its a software - "Hardware Assisted" card.
a true HW card keeps all the raid and management stuff (Define arrays, rebuild , of swap etc...) in the card's on bios management app. The OS sees only a standard IDE/SATA/SCZ drive. anything other then that is not a true HW card.

Nope, whether it's a full hardware RAID card or not it still needs a driver. There isn't just one driver for all SCSI controller or all IDE/SATA controllers so why should RAID cards be any different

The only time this is different is when it's a zero channel controller, but then you still need a driver for the SCSI HBA it's connected to.

[FatBastard]

Granted the usage of the term "Driver" is a little loose. of course each Hardware device needs a driver so the kernel can load it, even a plain old IDE controller needs a driver (like u mentioned), However HW card would reflect to the OS as just a plain old SATA II. if you can define the arrays, rebuild the raid , hot swap and handle all the raid level stuff before the OS loads, then it meats my requirements.
anyway, it looks like I'm gonna order an LSI MegaRAID 300.

[Evildead666]

I set up the RAID, and everything, before the OS loads.
Twice the OS has told me that the Stripe has failed , even though all 4 disks were fine, even to the OS and the Intel matrix thing which I installed, cos you have to install the basic driver...after a check in the Intel Matrix Bios, all was fine, with no lost data.
Will teach me not to remember which cable goes where.

I think what you are looking for is a RAID card that offloads the maximum of the processing to the Card, and off the CPU.

In which case, just check out any RAID cards that come with memory onboard. They usually use that as a buffer, and have a ARM or Intel chip or 3ware to take care of most of the work.

the LSI MegaRAID 300 looks absolutely fine. 128Mb cache, and the possibility of a daughter card for battery backup.

Let us know how it works out


I use my RAID for speed rather than fast I/O per second, so I haven't tested it for that.

[Gurm]

Hey don't complain if the driver offers you the CAPABILITY to manage the RAID. The LSI will do what you want. It's an awesome card.

[DGhost]

Forgive me for not getting it, but I still see absolutely no reason what you are trying to achieve using a "hardware" RAID controller.

It has been an "open secret" for a long time that once processors hit ~1Ghz "software" raid (to include SOFT RAID controllers and especially OS level RAID implementations) has able to be performance competative with hardware raid, often beating it on newer platforms. Especially in raid 0/1 configurations. and most especially when running a newer dual core processor.

further... this whole software/hardware raid driver debate is pure nonsense... as others have stated, it doesn't matter which controller you have, it still is going to take a driver. what you wind up with when dealing with companies like LSI or 3Ware is very limited compatability with Linux distro's and Kernel versions. Yes, a kernel is a kernel and all that bullshit. but when they release a package for a certain OS version, it contains modules compiled against a certain patch level kernel. it's not something that you can just snap your fingers and make work in another distro or with another kernel.

this is one of the reasons these products are so expensive. they certify their products with other products, and then can offer support for those products. And because they release closed source binaries, you wind up having to impliment your server software around what hardware you choose to run.

And as far as the OS seeing only a standard IDE/SCSI drive of the RAID array... that is almost always going to happen for compatability reasons, and it's going to happen regardless of if you are using a software or hardware raid controller.

I usually ignore these kinds of threads but I've read way too much mindless drivel in this one to pass it up... I could go on and on (and ON) about this shit...

oh well, i'll just be nice and sum it up here. there is no reason for you to waste your money on a hardware card, and more than likely you are going to run into compatability problems and decrease disk i/o performance by doing it. but thats you choice, because it's your money. so enjoy.

[Technoid]

What he (FatBastard) wants is essentially a raid "Dongle", something that plugs into his sata port in one end and into the drives in the other end.

Those are the only that wont have a driver

Those things do exist since I've seen them, I just can't remember where

[DGhost]

I have too. Most, like this one, are not designed for the sort of things he is looking for. The ones that are, like this one or this one, are usually flakey at best, have a tendancy to lower performance, and can lead to any one of a number of issues. They also are ridiculously expensive.

another note... modern "Zero Channel Raid" configurations still require drivers. What they are is a standard RAID controller that has no native channels - it simply uses the ones on the motherboard instead. The device itself still needs a driver to function properly.

[FatBastard]

Forgive me for not getting it, but I still see absolutely no reason what you are trying to achieve using a "hardware" RAID controller.

It has been an "open secret" for a long time that once processors hit ~1Ghz "software" raid (to include SOFT RAID controllers and especially OS level RAID implementations) has able to be performance competative with hardware raid, often beating it on newer platforms. Especially in raid 0/1 configurations. and most especially when running a newer dual core processor.

further... this whole software/hardware raid driver debate is pure nonsense... as others have stated, it doesn't matter which controller you have, it still is going to take a driver. what you wind up with when dealing with companies like LSI or 3Ware is very limited compatability with Linux distro's and Kernel versions. Yes, a kernel is a kernel and all that bullshit. but when they release a package for a certain OS version, it contains modules compiled against a certain patch level kernel. it's not something that you can just snap your fingers and make work in another distro or with another kernel.

this is one of the reasons these products are so expensive. they certify their products with other products, and then can offer support for those products. And because they release closed source binaries, you wind up having to impliment your server software around what hardware you choose to run.

And as far as the OS seeing only a standard IDE/SCSI drive of the RAID array... that is almost always going to happen for compatability reasons, and it's going to happen regardless of if you are using a software or hardware raid controller.

I usually ignore these kinds of threads but I've read way too much mindless drivel in this one to pass it up... I could go on and on (and ON) about this shit...

oh well, I'll just be nice and sum it up here. there is no reason for you to waste your money on a hardware card, and more than likely you are going to run into compatability problems and decrease disk i/o performance by doing it. but thats you choice, because it's your money. so enjoy.

Well ..... two different issues were discussed in this thread (ok, ok ,mindless drivel) cheap hardware raid cards (asked and answered), and software vs Hardware raid. now you've risen a 3rd issue, your agony of having to go through "these kinds of threads". unfortunately I have no valuable input addressing this new (for me) issue. for that I'm deeply sorry. I might have some trouble sleeping tonight, However history has taught me that's nothing Vodka can't fix.

[DGhost]

Vodka can fix everything, except waking up with the knowledge that you spent a sizable chunk of change on a card that is less compatable and lower performing that features that are probably integrated into the motherboard you have.

those "discussions" were essentially you discounting the advice that others gave you, for reasons that make no sense and have no technical merit. Indeed, there was no real discussion. And that is what is going to lead to the fun times you are going to have.

So yes. Enjoy your vodka. You're gonne need it.

[az]

Better yet. You two make nice noises from now on, you buy a cheap external RAID cage and donate the rest of the money equally to the MURC server fund and the AZ Vodka fund.

[Gurm]

Hmm... no no no. There is a general MURC liquor fund. Has been for some time. Send all donations to my house, I'll make sure it gets divvied up.

[DGhost]

I don't endorse Vodka anyways. If it was whiskey, maybe