Portal Home > Knowledgebase > Articles Database > Please help me to build RAID 0 or raid 5
Posted by AndyJ, 08-23-2007, 01:59 PM Hi guys, I'm trying to build a physical raid 0/5 that can plug in to any computer which has SCSI behind it. What are components you recommend (case, cpu, motherboard, SATA ...)? This is first time raid builder so i don't really need an expensive components. Thanks alot.
Posted by macker, 08-23-2007, 02:33 PM What are you trying to achieve by using RAID? Performance, reliability, expansion, ... ? What's your budget for the drives and controllers, what's your desired capacity, what kind of fault tolerance do you require? 3ware makes excellent cards for SATA RAID. SATA drives are a great option for low-budget RAID setups, because the drives are relatively cheap. SAS/SCSI drives tend to be very expensive, especially at higher capacities. E.g. you can get a 750GB SATA drive for a couple hundred USD, but you'll pay more than double that for a 300GB SCSI drive. SCSI drives are faster, do better under heavy load, are more reliable, and generally have a better warranty. Many SATA drives will only have a 1 or 3 year warranty, though that's getting better... SCSI drives typically have a 5 year warranty. But you pay a significant price premium. RAID helps equalize things; the fastest SCSI drive cannot come close to touching the throughput of two SATA drives in RAID 0 (though the SCSI will probably have better latency for short random seeks). RAID (other than RAID 0) allows you to handle one or more drives failing, without losing data. Drives will fail eventually, regardless of SATA or SCSI; RAID protects you for when it does happen. SCSI (and it's newer form, SAS) are both typical of better quality (higher end) servers. The use of IDE and SATA in servers has traditionally been reserved for the lower-end, where the driving factor is cost. That's still the case, but there are now much better options in quality for SATA based servers. My gut reaction is to say "forget about SCSI, get a 3ware 9500 card and some Seagate 750gb SATA drives, but get the more expensive version". WD and Seagate are my preferred vendors for SATA drives, but both have models designed for desktops vs. servers, the server models are slightly more expensive (e.g. 5-10% more), but are better suited. E.g. for WD look for "RAID Edition". Seagate vs WD is brand preference, unless you have specific requirements (e.g. WD's SATA Raptor or Seagate's SCSI Cheetah), both are excellent brands these days, I personally lean towards Seagate. Everyone will have had a bad experience with a brand, have had lemons, etc., don't let individual experiences sway you, but if you hear nothing but bad, or consistently agreed that a certain application (that's important to you) is problematic, take note. For the rest of the components, this depends entirely on what you're trying to achieve. Rackmount? 1U, 2U, 3U, 4U? Are you trying to achieve maximum density, or do you have space to spare? Do you need hot-swap? (If you can shut the system down to replace a drive, without worrying about 5 minutes of downtime, you don't "need" hot-swap.) CPU and motherboard don't really matter that much, though in rackmount your choices are more limited... if it's a desktop board, don't go with the cheapest model, look for good reviews, and things like solid capacitors, voltage regulators that are more than 3-phase, etc. If it's a server board, they all should be reasonable. Make sure you size the PSU properly, and that it's a quality PSU. (If it's a desktop PSU, and it doesn't have active PFC, move on.) The better you define your requirements and state your objectives, the more accurate the answers will be, and the more useful information you'll receive overall.
Posted by AndyJ, 08-23-2007, 03:44 PM I think expansion is best for me right now. Capacity ~2TB is good for me. For fault tolerance, i think raid 5 is what i am looking for Yea, SCSI drives are expensive. I may not go with SCSI then I probably go with 4U or desktop case. No need space to spare. I don't need hot swap either. That's good to know. Here is my list of components: 4U rack, or desktop case ASUS Motherboard + CPU AMD 4400+ 512MB RAM 3ware SATA RAID controller 4x 500GB WD HDD Anything else that i missed in that list above ? software, OS, hardware? what cable do i use to connect that raid to other computer ? Thanks
Posted by DaKine, 08-23-2007, 04:00 PM Macker - Nice detailed explanation. AndyJ - If you really want to go cheap and you already have a licensed copy of Windows 2K3 Enterprise Server you can buy a cheap 4 port hard drive controller card and use the software RAID capabilities of Windows. The hard drive RAID controller would be better (and faster) in case of a problem but it would be more expensive compared to a regular hard drive controller. Or if your motherboard already had 4 ports available you could use the built-in controller. This is only a suggestion and not the best solution but it would be cheaper if you already had the OS. Also, you could boot your RAID box from the RAID so you won't have to purchase a 5th drive to install the OS on. Just be aware that 4x500MB drives in RAID 5 will only give you ~1.5TB since one drive will be held as a hot spare. If you are not too worried about transfer rates, why not just put the box you build on your network so all of your systems can access it? That will make it pretty easy for you to connect and cheaper as well since a network interface should be built-in to the MB. I hope this helps! Dave
Posted by macker, 08-23-2007, 04:34 PM Go with at least 1GB of RAM, preferrably 2GB. CPU can be slower, RAM is what will kill the performance. For CPU, the clock speed (4400) can be lower, just try to stay with a higher FSB, and make sure the RAM supports the maximum FSB speed. The big benefit to the RAM on a file server is disk caching; this makes it faster, since it spends less time having to read stuff from the disk. Remember, for a RAID 5, usable capacity is N-1, so 4x500 is 2TB total, but only 1.5TB usable. 4x750 is 3TB total, or 2.25TB usable. If capacity is the goal, go with the bigger disks now. For the 3ware controller, I would go with a 4-port or 8-port. Are you going to fill up 2TB in 6 months? 12 months? Remember, disk drives will keep getting bigger, and cheaper. New RAID controller models will come out. Don't overbuy today for what you can upgrade tomorrow. You can always buy a second 3ware 4-port controller later, and it'll be about the same overall cost as if you bought an 8-port today, but you may get a newer model, and a fresh warranty. I use Linux based distros almost exclusively. Linux is a fine choice for a file server, and there's various distros that include web control panels to help you configure them, etc. Look for something based on CentOS or Whitebox Linux, or another "RHEL clone". Something based on Fedora does work, but since this is just a fileserver, I'd prefer the RHEL-based version.. it's more stable, and you can apply any updates without worrying as much about breaking things. Normally, you would connect a fileserver to your network, and access it via an Internet protocol, like samba (windows file sharing), FTP, NFS, etc. More sophisticated methods like iSCSI or fibre-channel are probably over-spec'd for what you're doing. Again, this comes to questions of ... how are you going to use the space, how do you want to access it, single user or multi-user, accessed by trusted users or untrusted users, multiple systems or a single system, etc. For 4 drives, you can run with a smaller case... a 4U case should accomodate around 12 to 16 drives, but will be very heavy, and draws lots of power (e.g. may idle at 5 amps). Again, don't buy more than you have a practical use for, you can always upgrade later. If it doesn't have on-board video, you'll need a cheap video card. Finding a PCI video card can actually be a pain, onboard video is very convenient, and should be standard on a server motherboard. If going with rackmount, look at Supermicro and Tyan for motherboards. Supermicro has some nice "bare-bones" chassis configurations that may fit your needs; e.g. I run 6014's with 4 250GB drives and a 3ware 9550 in a 1U configuration all the time, but this should easily support 4 750GB drives instead. Last couple desktop-based fileservers I've built... one was in a Supermicro SC750A full tower case, and I used 2 3ware RDC-400-SATA hot-swap cages (NOT recommended) hooked up to an 8506-8LP ML. Had to buy break-out ML (MultiLane) cables, because the cages don't have ML connectors. It's not a bad setup, just the cages are not high quality; they're built in China, not by 3ware/AMCC directly. That was running an SMP Pentium Pro setup, and 1GB of RAM, with Samba to put it on the network as a Windows fileshare. Another was a single P3 800, 512MB RAM, 3ware 7506-4LP to 3 160G Seagate's inside a very nice Lian Li case. Spending some extra money on a good quality case will not only help with airflow, but will limit the amount of blood you shed. I'm actually upgrading this same system today, dropping in an Asus P5K-V motherboard, Core 2 Duo CPU, and a new Antec NeoHE 550 PSU. This is to support a new PCI-Express 3ware controller and additional array. I like dual CPU's on servers, just in case one gets overloaded; a single thread burning 100% CPU typically cannot deadlock an SMP server. This server sees very light use at low traffic rates, which is why it only has 512MB RAM; the upgrade will take it to 2GB RAM, and it's going to see much more traffic (media library). One other thing... if this is going to be in a datacenter, go with high CFM fans, noise be damned. But if this is going to be in a residential or business location, within 20' of people, keep an eye on the dB rating. Spending an extra $10 on quality quiet fans is a worthwhile investment. But regardless, never buy sleeve bearing fans; they're junk and not worth the small amount saved. For cheap rackmount, I would absolutely go with a Supermicro system, and would readily recommend one of the pre-built systems. Just be sure to buy from a reputable dealer. You may choose to go with cheaper RAM instead of one of the Supermicro "certified" (tested) parts, or go with a gray market CPU (eBay) instead of something from retail channel; these are up to you, and depends on what kind of support you want if the part fails, and how much that's worth in savings to you. If you prefer AMD over Intel, most of Supermicro's offerings are available with AMD boards; look under the "A Plus" line; same chassis, different model # and motherboard. One note, though; most rackmount systems and motherboards are designed for "server CPU's" (Xeons and Opterons), which are more expensive than the "desktop" counterparts, but for light duty, a desktop CPU is perfectly adequate. The Xeon or Opteron is a better choice when you're trying to extract every last ounce of performance from a single system.
Posted by AndyJ, 08-23-2007, 04:38 PM Yes, my company purchase couple license for window 2k3 server but not sure they are used all. I will check if there is any spare one. For 4 port RAID controller card, not sure which one good. does this one good http://www.highpoint-tech.com/USA/rr1640.htm I wish i could use it for network too. Does Win 2k3 server have option to set this box acts as storage thru network ? Thanks
Posted by kgs_namboothiri, 08-24-2007, 02:44 PM you want create soft raid or hard. You can create raid in the time of installation of OS.otherwise you can use the raid commands.If need a help please mail to me i will give you the details. kgs_namboothiri@yahoo.co.in
Posted by DaKine, 08-24-2007, 02:54 PM Never heard of that RAID controller before so I can't say either way. When you create the RAID storage in W2K3 you can format it and assign a drive letter and then share it across the network just like any other storage resource. Dave
Posted by plumsauce, 08-25-2007, 02:41 AM the whole point of raid is reliability. i recommend that you do it right. to me that means scsi, battery backed cache, raid 10/50, redundant power supplies, redundant fans, you get the picture. this is our standard setup. we get to sleep at night
Add to Favourites 
Print this Article
