home server, raid 3 or 5?

I'm planning on building a small home server for all of my storage/backups in the future.

i cant decide if RAID 5 or RAID 3 would be better suited.

for a 3 drive configuration, i think RAID 5 would give more storage, but less speed writing/reading while RAID 3 would give much more speed at the loss of 1/3 of the space.

Should i go for RAID 5 or RAID 3 for 3 hard drives?

which is the BEST configuration for any amount of drives up to 6?

i need fault tolerance, but speed is always wanted...(even though a max of 5 computers would be reading from/writing to at ANY time...)

On my proliant im running Raid 5 with 6 9.1gb Scsi 10k rpm drives, Raid 5's read is uber fast but just depends on the drives, what type of drives are you planning to use..?

For "home server", might I suggest a cheaper alternative? RAID-5/3 cards are not cheap and many don't come in normal PCI format. They have dedicated processors and cache memory to do the parity calculations and so the price of such cards is - uh, big. Also they are slower on writes than comparable RAID-1 mirrors due to the parity calculations involved.

Get a card with a Silicon Image 680 chipset - a 2-channel ATA RAID card with normal PCI interface and allows you to do RAID10/0+1. These are inexpensive yet perform well, and RAID10 whilst having a 100% overhead is still going to be a lot cheaper than RAID5/3. IDE drives are also cheap

you really think raid 1/0 would be cheaper?

when i first had this idea i was planning on the new 400 GB drives, but then i realised i wanted this server allot sooner, and, well, i'm poor

So, whatever i can get for a good deal. maybe a few 20's, maybe some 40's...i dunno yet...


maybe i should just get 4 drives and use the onboard controllers? i'll bet linux could do a good job of using the masters as raid0 and having the slaves do exactly the same thing... but i dont really know.

just curious, are you going to be using gigabit lan as well? i think you could find a larger increase in transfer speed from that than from using raid. and for less too. that said, i think raid 10 might be a good option for a smaller server. have 2/3 of your total (after raid) for raid 0, then have 1/3 for vital data. or just go for full out raid 0, and backup the really important stuff on another machine.

also, im kinda thinking that your planning to use this as a server for all you friends over VPN. You really dont need much to max out your dsl connection, i could easily do it with my pentium pro router at 266 mhz. think 256 kbps upstream at max, thats if you have the good package. i think the most i would put on a dsl connection without feeling its a waste is a 700 mhz machine with maybe 384 ram. and thats for a game server. but i could be wrong about your intentions.

and 40gb drives are usually a good deal.

the server will be my all out file storage. My rig will eventually run raid 0, and backup nightly to the file server. i will also do weekly backups of the other machines to the file server. As well as store all of my stuff on it, such as my DVD's, music, and cd images.

I will set it up for VPN acess, but noone will have the password to acess stuff like DVD's, CD images, or my music, because that would be illigal.

basically there will be a single folder for sharing with others, but the main use for the server is around my house...as i like to have acess ot all my resources no matter where i am. like music. or a utility. probably map it as a network drive and install stuff to it, so i could have local machines with pitiful drives.

i'd like to do this with linux and something like a 133 i could throw together, my main interest is storage, as thats all it will be. a friend would be halping me with the software part of it, i just dont know how to go about the stoage...buying 4 40's and getitng 80 GB of storage just doesnt sound good to me...as raid 1/0 would do...my biggest qualim is i want laods of storage...loads. but it needs to be stable, because if i lose everything, well, i lose everything. dont want to backup to an unstable source, do we?

If you got 4 drives, make a RAID 1 and a RAID 0 array. Eh?

Hardware XOR RAID 5 is the real way to do it.

If you want the capacity for up to six drives you're looking at some expensive hardware: http://www.3ware.com/products/serial_ata9000.asp

Four drives something like: http://www.promise.com/product/product_detail_eng.asp?productId=112&familyId=2

But as someone else pointed out your network connection will become your bottleneck. 100mbit is only 10mb/s. The best way would be to find a cheap i865 board with intel CSA LAN and a celeron so that the NIC and RAID 5 card aren't fighting over the PCI bus. You should be able to run up to 70~80mb/s with fast drives.

eh, yeah. i'm thinking that if you don't want to do raid 1, and your concerned about stability, that raid altogether isnt for you. maybe you should just share each of the drives on the machine seperately, without raid. this way you can limit the damage of a drive failure. you might lose 1/4 of your data, but it's not all of it, so whatever.

i think you will find the performance fine as long as you use gigabit lan. also, if you do decide to use gigabit lan for your server, i think you might need something with a little more oomph than a p133. try shooting for around 600-800mhz. a celeron sounds like a good idea. but again, remember that you will only see the benefits of raid after you have gigabit lan, because a normal drive can overwhelm a 100megabit connection easily. it's only with gigabit where the hard drive becomes the limitng factor.

well gigabit lan isnt an option, i jsut got 100 base not long ago...

and i'd like to lose NONE of the data, thats why i'd like raid...because my data is important to me.

"If you got 4 drives, make a RAID 1 and a RAID 0 array. Eh? "
...
"buying 4 40's and getitng 80 GB of storage just doesnt sound good to me...as raid 1/0 would do..."

because thats raid 1/0, or 10 as some people say, and its a bit wasteful...

Como said:

"buying 4 40's and getitng 80 GB of storage just doesnt sound good to me...as raid 1/0 would do..."

Click to expand...

I mean have two seperate arrays. Total space would be 120 Gb and one would be backed up fully as RAID 1, the other light and fast RAID 0. That way it's also flexible and a heck of a lot faster than RAID 5. (And cheaper)

Cjwinnit said:

I mean have two seperate arrays. Total space would be 120 Gb and one would be backed up fully as RAID 1, the other light and fast RAID 0. That way it's also flexible and a heck of a lot faster than RAID 5. (And cheaper)

Click to expand...

RAID 5 with 4x 40GB would give you 120MB, and it would all be backed up. Since he's stated he's going to be running 100mbs ethernet speed isn't going to be an option, and even if it was RAID 5 reads are quick as it's like reading from a four disk stripped array. Plenty fast for media storage and playback anyways.

this is Como...

how do you intend to get RAID 1/0 with 4 40s and have 120gb?

RAID 1 is mirrored, so the total space equals have of all drives.

is it possible to have a RAID array that can be expanded simply by adding more drives?

Some RAID 5 controllers can add disks non destructively. Look for one that supports "online capacity expansion" or "online disk expansion".

eeexelent. thats another reason to go raid 5.

about how many MBS would a 3 disk 7200RPM raid 5 write?

Como said:

eeexelent. thats another reason to go raid 5.

about how many MBS would a 3 disk 7200RPM raid 5 write?

Click to expand...

Thats like asking how fast my car will run the 1/4 in, with out giving any specifications.

What drives are you going to run, what controller, stripe size ect? Even still we will not be able to give you anything that is really helpful, as RAID arrays all act differenetly. There are too many variables to say for use. I think your best bet might be to look on line for some RAID 5 benchmarks, and see what you can turn up. Remember that 3 drives is the minium, but the more drives you add the bigger and faster the array, in most situations.

Como said:

About how many MBS would a 3 disk 7200RPM raid 5 write?

Click to expand...

A hardware XOR engine should be faster then your 100mbit ethernet.

Here's some reviews to browse over - both support online drive expansion:
http://storagereview.com/articles/200106/200106132400A_1.html
http://www.xbitlabs.com/articles/storage/display/adaptec-2410sa.html

I have a RAID 5 in my file server. It's 4x 160 gig Maxtors on a 3Ware Escalade 7450. That's a 64/66 PCI card. I have a MSI K7D-Master dual Athlon board in there (running a pair of Duron 1.3s). Total useable space after parity striping is 480 gigs. It sits over in the corner and streams all my movies and music.

RAID 5 is a good solution for 3+ disks in a file server because it's efficient on space while at the same time offering fault tolerance and good I/O performance. All in all it's the best compromise you're going to find, and the cost of the controller should be offset by the amount of money you'll save through buying less disks to get the same amount of storage space.

well thanks for the info, i still dont know about disks, i may even go SCSI, if i can get cheapish drives. My biggest concearn is cost.

At one point, i heard people talking about putting different hard drives (like a 120 gig and an 80 gig) into a form of raid 0. Is it possible to use non-identicle drives in raid 5? i wouldnt think it would be, but it may. i only know the basics of it...

I *may* be gettingmy hands on a motherboard/cpu/ram from an dell, that would be a 1.78GHZ PIV with 256 megs RAMBUS, and i would probably use this as my file server. is it overkill for hardware raid? i think it may be as all the work is really on the card...so i may use it for something else instead, if i even get it... other than that a 500-900 mhz machine will probably be the best i can dig up for a storage unit.

Now, i just remembered that the PCI buss is limitied to about 133MB/S throughput (or waht that Mb/S? i forget) so i'm not worried too much about the storage itself being too slow...

What i'm not interested in, is would it be better to go IDE or SCSI? i mean, the biggest issue is cost, but if one can give me twice the performance for 25% more, i have to think about it. I'm assuming that IDE is the best choice for cost and speed, but SCSI may be worth a look, as its always nice to learn something new.

CONTROLLER CARDS! what should i use? whats a good brand? looking for standard PCI, this isnt anything fancey I read Adaptec was the best, but i've also read that a mac is the worlds fastest PC...Whats the general concensus? OOh, and one with "online capacity expansion" so i can add another later would be nice, i dont want to have to back up my backup machine for upgrades

I currently own a WD 120 gig ata100 7200 rpm 8mb cache drive....would two more of these make a good start? is it possible to mix one of these with one thats 2mb cache in raid?

On a 100mbit ethernet connection I don't think you'll see any noticeable speed difference between SCSI and SATA. If you bought high end SCSI drives you'd get faster seek times, but we're talking about 5ns vs 7ns here, and a huge price difference.

Most controller cards will let you use different size drives, but they'll base the array size off of the smallest drive (ie: if you had an 80 and a 120 the controller would use the 120 as an 80).

Yes you can mix drives with different caches, it's a case of "the array is as fast as it's slowest drive". Considering the price difference (CDN$10 here) I'd just get two more 8mb ones.

My Dad uses two 160gb 5400rpm drives in a mirrored array to hold music and stuff, and he finds it plenty fast so I don't think you'll have any problems with a 7200rpm SATA RAID 5 array.

Some people like Adaptec, some don't. Most people like 3ware and LSI.
$319 - 4 port Adaptec http://www.newegg.com/app/viewProductDesc.asp?description=16-103-137&DEPA=0
$300 - 6 port LSI http://www.newegg.com/app/ViewProductDesc.asp?description=16-118-011&depa=0
$239 - 4 port LSI http://www.newegg.com/app/ViewProductDesc.asp?description=16-118-015&depa=0
All three support drive expansion.

Seeing those prices I'd lean towards an LSI controller. They're all 64/66 cards but will also work in 32/33 slots.

Althornin in the 2cpu.com forums: "I've got an LSI 150-4 controller, in a 32bit/33mhz pci slot, and i get 45MB/s writes and 60MB/s reads with 3 WD 160GB drives."