Raid 5 question

[Everfalling]

ok, i have 4 300 gig maxtors i wanna tie together with Raid5, but at the same time i wanted to get a 5th to round it up to a TB. so far, finding a controller card for this seems nearly impossible, or at the very least, very very expensive. so i'm thinking of just using my onboard controller and lose one of the 4 drives to parity. also, since my 7800 gtx sticks out inside my case so far, it actually prevents me from using one of my 3.5" drive bays... so i couldn't support anything over a total of 5 drives anyways. ok, so my question is, let's say i have 4 drives on raid 5, but then i buy another drive. is there a way to add a drive to Raid 5 after everything is already set up? or do you basically have to have all the drives you're going to use right there when you make it? Also, let's say i DO get that controller card and the space for a 6th drive, can i disconnect the drives and transfer them over to the controller? pretty much the problem is, even though i doubt i'll fill 900 gigs of space, i have enough stuff already where backing it all up to move the drives might be a problem... so, any do's, don't's, can's and can not's would be great.

 

[eth00]

Some controllers support expandable arrays BUT it is going to come at a cost premium. If the card does not mention anything about being able to expand the arrays live -- it does not support it. Chances are on any of the controllers you are looking at you will not find it. I don't know if there are any controllers that even support expanding to an entirely new card, usually for the expansion to work you get say a 6 port card with 4 drives and just add 2 more later.

The short answer - no you cannot add more drives and get the space w/o formatting on that setup. If you want a cheap solution linux software RAID with a controller card to get the needed IDE ports. If you are running only windows I would shy away from software RAID I have heard too many horror stories of it dumping and loosing everything.

 

[unhappy_mage]

The Highpoint series is reasonably priced at around $200 for 8 ports; the 2220 is recommended so you can expand the array. I'd suggest going with an offboard card rather than onboard just so you can migrate the array when you buy a new motherboard.

 

[Everfalling]

The Highpoint series is reasonably priced at around $200 for 8 ports; the 2220 is recommended so you can expand the array. I'd suggest going with an offboard card rather than onboard just so you can migrate the array when you buy a new motherboard.

do any of those come compatable for a standard PCI 32 bit slot? all i have is either a 32bit PCI slot, or a PCIe 16x slot.

EDIT: i found this model: RocketRAID 1820A

it say's it's backwards compatable with a standard PCI slot. does this mean it'll run on my Asus A8N-SLI Delux with just it's 32 bit PCI slots? oh please say yes

 

[unhappy_mage]

Yes, it will. You might consider the 2220 (for expansion support) or the pci express 2320, for future upgradeability. If you're not using two video cards, you can get the raid card in the other slot.

 

[Everfalling]

Yes, it will. You might consider the 2220 (for expansion support) or the pci express 2320, for future upgradeability. If you're not using two video cards, you can get the raid card in the other slot.

for the 2220, what do you mean by expansion support? and for the 2320, what do you mean by upgradability?

also, the 2320 runs offa pci-x, will that work with my PCIe 16x slot? i just wanna make sure that if i buy one of these i dont come up with a compatability issue.

 

[unhappy_mage]

2220: You can add drives to the array without destroying and recreating it. So you could buy 4 drives now, see how it fills up, and then buy a fifth if you need it, and expand.

2320: pci-x is the server version of pci. The 2220 is on pci-x; what you mean is pci-e or express. It should work with the second pci-e slot on the motherboard. I believe that board is 16/2 or 8/8, right? It should work in either mode, and x2 is enough for a raid array - 500 MB/s is plenty, you'd be lucky to hit that with 10 disks.

 

[Everfalling]

awsome. i'm gonna go with the 2220, cause i have 4 drives now, but i plan on adding a 5th later. this'll be perfect for what i wanna do. thank you SO much for pointing me to these.

 

[John G.]

Thanks indeed! These look like fine cards.

Sorry to interject into the thread, but I too am thinking of setting up a RAID 5 system where online storage expansion would be called for. The idea of RAID kind of scares me though, with compatability issues, and just the fact that everything's all bound together such that if something goes wrong, you lose everything. Obviously I'd like a card that is trustworthy.

I'm curious about the difference between the 2220 and the 2320-- is it just interface? Which one is the better choice for a server using a modern desktop motherboard? An older desktop motherboard?

Also, mage, do you have any suggestions on other cards that might hit that nice compromise of value (my cash is limited), features (online expansion is a must), and quality brand? Just so that I have something to compare these to? Or do the Highpoint cards kind of stand above the rest?

 

[Everfalling]

Thanks indeed! These look like fine cards.

Sorry to interject into the thread, but I too am thinking of setting up a RAID 5 system where online storage expansion would be called for. The idea of RAID kind of scares me though, with compatability issues, and just the fact that everything's all bound together such that if something goes wrong, you lose everything. Obviously I'd like a card that is trustworthy.

well, with what i've heard, unless you have a multidisc failure, raid 5 is actually pretty good with error protection, keeping one drive off to the side for parity. Compatability isn't very difficult considering all you gotta know is that Raid 5 requiers you to have the exact model and size for it to work. I'd be scared if running 0 but i think 5 seems to be the safest alternative other than +0.

 

[unhappy_mage]

The 2320 and 2220 seem to be very much the same card on different interfaces. I haven't heard anything to the contrary.

As to a better card (or even an alternative) I haven't found one. The sata2 cards on newegg are all more expensive, so ignore them for a moment. The sata1 cards: there are two pretty close to the price of the 1820, so let's look at features. The promise sx8 doesn't support OCE (and I haven't heard great things about reliability), so forget that. The broadcom BC4810 supports all the advanced raid features, but apparently requires a seperate license key to do raid 5. Thanks but no thanks.

There is an alternative, though - software raid with Linux. You need to be running linux, of course, on the box with the array in it, but you can build a seperate machine for it; this is something to consider anyways to avoid power supply problems - a high-end video card and a half dozen drives can mean problems. If you do this, you can buy something like Supermicro's AOC-SAT2-MV8 for about $130 and get 8 ports. EVMS does a heck of a job managing disks, and it gives good performance - 50 MB/s on three disks on my machine.

Everfalling: It's not really one drive that gets kept off to the side, that's raid 4. In raid 5 the parity is distributed, meaning that each disk keeps some of the parity.

Finally, which card for which motherboard. For a modern desktop with pci express, go with the 2320. It's more futureproof; pci express is the wave of the future. It's also about 8 times faster a bus than the standard 32/33 pci slot you're likely to have. If you've got an old desktop board, the 2220 is a good choice, but I'd tend to go find an old server board instead. Why? 64/66 or better pci slots. They're plenty fast for a raid array, they're cheap (I got a dual p3 board and chips for $105 on eBay) and they're stable platforms. If you can find a Supermicro board, I'd strongly recommend it.

I hope I've answered all your questions, but feel free to comment/add more questions. This stuff isn't cheap, so you're better off finding out everything you can now rather than when it's too late.

 

[Joe Fission]

Compatability isn't very difficult considering all you gotta know is that Raid 5 requiers you to have the exact model and size for it to work.

As far as I understand, RAID 5 does not require you to have exact model and size of drives in the array. However, the array size is based on the capacity of the smallest disk in the array. So, if you have an array of 300GB drives and add a 500GB drive to replace a failed one, or to expand your array, the array will only use 300GB of that drive. The drives don't have to be of the same brand either as far as I know.

 

[Everfalling]

The 2320 and 2220 seem to be very much the same card on different interfaces. I haven't heard anything to the contrary.

will the 2320 allow for 'on the fly' drive expansion like the 2220 seems to allow? meaning, if i get the 2320, put 4 drives on it and set it to Raid 5, does the card allow me to put on a 5th drive afterwards, or is that only for the 2220? i'd like the speed and 'semi future-proof' interface of the 2320, but i kinda like the adding drives at the last minute aspect of the 2220, esp since all it's going to be is for storage.

 

[unhappy_mage]

The 2320 also has OCE. Check the linked spec sheet.

Raid 5 can mix and match drives, but that doesn't make it a good idea. You get different buffer sizes and strategies, different seek times, and different generation drives, and that leads to slowdowns. You shouldn't have any problems as such - the array will still work, but it'll be slower than with all identical drives.

 

[Everfalling]

i think i might have hit a pitfall. i'm looking at the RocketRAID 2320 card's compatability chart, it's got my motherboard on there (Asus A8N-SLI Delux), but not my specific model of hard drive. i have 4 300 gig maxtor 6L300S0's, but the sheet says it's only compatable with the 300 gig 7L300S0. is this a problem? the 6L300S0's were cheaper than the 7L300S0's. i didn;t think i'd need to be worrying about compatability with a controller card at the time. do you think it'll still support the drives i have?

 

[eth00]

As far as I understand, RAID 5 does not require you to have exact model and size of drives in the array. However, the array size is based on the capacity of the smallest disk in the array. So, if you have an array of 300GB drives and add a 500GB drive to replace a failed one, or to expand your array, the array will only use 300GB of that drive. The drives don't have to be of the same brand either as far as I know.

Most cards will let you run different drives but I would not suggest it. Mixing the different specs on the drives can cause problems for the array and if you are spending enough money to pickup 300gb drives you may as well do it right.


As far as drive compatability - usually the only real thing you have to worry about is the capacity. Highpoint is a cheaper card and I am used to only the server cards so there really may be a limit. If nobody can tell for sure if it works mayeb drop them an email or search on google to see if anybody has a similiar configuration.

 

[unhappy_mage]

I wouldn't worry about the "compatibility chart" for hard drives nearly as much as the one for motherboards. Sata is a lot more tolerant of different speed drives/controllers, different feature sets on opposite ends, that kind of thing. I didn't even check when I bought my controller and drives whether they were "compatible" with each other, and haven't had any problems at all.

It can't hurt to drop them an email, though. Good luck!