Is RAID 5 worth it?
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I have an xfx nforce motherboard. I use the onboard RAID 5 (2 x 250GB striped 1 x 500GB mirror). It's seek times, and read write throughput are slightly better than a single drive. One thing that is important to mention that I don't think anyone else has so far: The stripped drives should be the same model HD. If you are scrounging a bunch of HD's together that have been laying around and try to make a RAID 5 it's not going to work to well. RAID 0 sure, but any of the RAID levels that deal with parity should be on identical drives (for the striping anyway). Also note, in my board (which cost much much less than $600) RAID is indeed implemented at the hardware level. Software RAID is using the compmgmt.msc's Disk Management(local) Snap-in to create a RAID array. While the performance of RAID5, on my motherboard, isn't going to beat a $600 controller, it isn't the same as Software RAID. Think of onboard graphics cards, at the hardware level they use some RAM and they use some CPU cycles, but they aren't doing "software rendering" (which if anybody HAS used before is way way way worse than an onboard graphics card). In the end, my system isn't screaming speed, but it isn't slow either and all of my data is backed up against a hard drive failing, for my important stuff that I can't loose, I FTPS it off site (the only protection against fire, flood, theft of equipment, data corruption, etc). Well that's my two cents anyway. :zzz: :zzz: :zzz:
Member 4611134 wrote:
Also note, in my board (which cost much much less than $600) RAID is indeed implemented at the hardware level. Software RAID is using the compmgmt.msc's Disk Management(local) Snap-in to create a RAID array. While the performance of RAID5, on my motherboard, isn't going to beat a $600 controller, it isn't the same as Software RAID.
Unless you paid a several hundred dollar premium (over an otherwise identical but nonraid version of the board) it's not hardware raid, even thought your mobo (or a cheap "raid card") has a "raid controller chip" on it. Real hardware raid has either a microcontroller or asic to do all the parity calculations. Fake hardware raid has a chip that says "I'm a raid controller" but offloads 100% of the work to the CPU just like pure software raid. This results in something as slow as software raid, but which is also tied to a specific controller. Pure software raid at least has the advantage of being portable. :doh:
It is a truth universally acknowledged that a zombie in possession of brains must be in want of more brains. -- Pride and Prejudice and Zombies
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Member 4611134 wrote:
Also note, in my board (which cost much much less than $600) RAID is indeed implemented at the hardware level.
I will guarantee that it is not a hardware controller. It is just a plain old SATA controller with a bios that can boot create and off the array and a driver that in windows does the software raid. If it were a true hardware controller it would contain a dedicated raid cpu of 200 MHz to 1GHz with an external cache and external battery pack (that is larger than a cell phone battery) to supply hold cache memory in the event of a power outage. After the power is restored this cache gets flushed to the disks.
John
Using motherboard raid (RAID 5 2x250GB 1X500GB) : Random Access : 10.3 ms Average Read : 96MB/s Single SATA Drive (500GB): Random Access : 12.4 ms Average Read : 88.5MB/s So in my situation, for whatever reason, a single drive is in no way faster.
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Member 4611134 wrote:
Also note, in my board (which cost much much less than $600) RAID is indeed implemented at the hardware level. Software RAID is using the compmgmt.msc's Disk Management(local) Snap-in to create a RAID array. While the performance of RAID5, on my motherboard, isn't going to beat a $600 controller, it isn't the same as Software RAID.
Unless you paid a several hundred dollar premium (over an otherwise identical but nonraid version of the board) it's not hardware raid, even thought your mobo (or a cheap "raid card") has a "raid controller chip" on it. Real hardware raid has either a microcontroller or asic to do all the parity calculations. Fake hardware raid has a chip that says "I'm a raid controller" but offloads 100% of the work to the CPU just like pure software raid. This results in something as slow as software raid, but which is also tied to a specific controller. Pure software raid at least has the advantage of being portable. :doh:
It is a truth universally acknowledged that a zombie in possession of brains must be in want of more brains. -- Pride and Prejudice and Zombies
If you read the entire post you would note that I wasn't disputing the fact that it offloaded the parity calculations to the CPU (similar situation for an onboard graphics card). I benchmarked it, and it is (as I said) only slightly faster than a single disk, however, speed isn't really the point of RAID 5. The point is that your data is mirrored without the performance loss of RAID 1. I can take my 500GB mirror drive to another computer and it has all of my data on it (the striped drives are a different story). The main point of RAID 5 is that if a single component in my computer fails, my data is safe, which is the case. However, if my mirrored HD dies at the same time that my motherboard dies, yes, I'll have a problem. If two HDs fail at the same time, yes, I'll have a problem. But you can't protect your data in a single system from a meteor strike. (Which is why I protect the really important info by FTPSing it off site). Before I decided on the setup that I did, I installed both ways, and benchmarked it. (I didn't think about trying pure software (in windows compmgmt.msc Disk Management Snap-in) RAID to see how it performed. I choose the method that required little intervention on my part to keep my data safe, and kept the performance alright. Note also, my system is SATA I, I don't know how SATA II performs as I haven't tested it. So before basing your choice on some article you read about how RAID will perform, see for your self, compare the numbers, and make a decision. Cheers :)
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Bob1000 wrote:
Thought RAID 5 was 3 or more disks - so if you have two it wouldn't apply!
Yes, I know. I currently have two disks but am thinking about getting a third one to go RAID 5. This discussion is leading me nowhere. I've learned a lot, but since there are people for and against it, I think I will do my own testing and see how it works :) Thanks everybody for your tips!! :)
Luis Alonso Ramos Intelectix Chihuahua, Mexico Follow me on Twitter (@luisalonsoramos) or on my blog (www.luisalonsoramos.com)!
After having failed at revovering a failed RAID 5 array (single disk failure initially) a few years ago, I would not recommend RAID 5 for anything other than corporate use (with an IT/support department). If one of the drives fail, you must replace it with an IDENTICAL drive (identical addressing and size). We had what was supposed tio be an identical hot spare, but it turned out to have a bad sector (hidden by formatting), which made the drive just a tad smaller. As a result, we couldn't rebuild the array. Since we were using high-end drives, we were able to order a replacement with the same model and revision (expensive). For a home system with less expensive OTS HD, replacement of a failed drive may not be straight forward. Unless your controller specifically allows variation between drives, this may be your deciding factor.
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I will be reinstalling my main PC with Vista x64 this weekend. I took the opportunity to upgrade the RAM and the hard drives. It had a 250 GB hard drive which I am replacing with two 500 GB HDs. I was thinking about going RAID 0 or RAID 1, or maybe just using the second HD for incremental backups. But somewhere deep in my mind a RAID 5 idea appeared. Do anybody of you use RAID 5 in your day-to-day computer? Is it worth it? How is performance? Supposedly, a bit better. What do you recommend?
Luis Alonso Ramos Intelectix Chihuahua, Mexico My Blog!
Hola Luis, saludos de un paisano :) En inglés para contribuir más al thread: We're currently working with around 20 servers equipped with 4TB raid-5 units (5 1TB drives) and the experience has been quite positive. We're not concerned with read/write performance, mainly information volume, so I can't offer an opinion regarding that aspect. The controller is hardware based (Intel) built directly on the motherboard. Here's our experience so far: We sparingly experience soft failures that are simply corrected by a rebuild operation (sometimes taking around 25 hours to complete); we experience a noticable slow-down, but we still manage to be fully online. We have survived 6 single disk failures so far (in a one year period) with no problems at all to rebuild and minimal off-line time (we have no spare disk installed). We also have had only once a simultaneous-dual disk failure and fortunately we were lucky enough to recover virtually all information using a wonderful commercial tool. :cool: One CRITICAL factor is temperature. Try to keep your drives with good spacing between them and if possible, install additional fans to keep your drives cool. This greatly reduced the time between soft failures. In a nutshell, I would strongly recommend hardware based raid-5! ¡Saludos! Gerardo
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Hola Luis, saludos de un paisano :) En inglés para contribuir más al thread: We're currently working with around 20 servers equipped with 4TB raid-5 units (5 1TB drives) and the experience has been quite positive. We're not concerned with read/write performance, mainly information volume, so I can't offer an opinion regarding that aspect. The controller is hardware based (Intel) built directly on the motherboard. Here's our experience so far: We sparingly experience soft failures that are simply corrected by a rebuild operation (sometimes taking around 25 hours to complete); we experience a noticable slow-down, but we still manage to be fully online. We have survived 6 single disk failures so far (in a one year period) with no problems at all to rebuild and minimal off-line time (we have no spare disk installed). We also have had only once a simultaneous-dual disk failure and fortunately we were lucky enough to recover virtually all information using a wonderful commercial tool. :cool: One CRITICAL factor is temperature. Try to keep your drives with good spacing between them and if possible, install additional fans to keep your drives cool. This greatly reduced the time between soft failures. In a nutshell, I would strongly recommend hardware based raid-5! ¡Saludos! Gerardo
Hello Gerardo, You bring up a good point: temperature. It's a desktop computer which currently has one HD, and if I put three in it, its fan might not be enough. What I wanted to do was something simple, and adding additional fans or power units is not simple :) I guess I am going to try RAID 5 with what I have right now, and depending on how it works, I'll keep it or go back to a single disk with one backup disk. Where are you from? What do you do? I see you are relatively new here, so welcome!! It's always nice to find someone from Mexico here :)
Luis Alonso Ramos Intelectix Chihuahua, Mexico Follow me on Twitter (@luisalonsoramos) or on my blog (www.luisalonsoramos.com)!
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I will be reinstalling my main PC with Vista x64 this weekend. I took the opportunity to upgrade the RAM and the hard drives. It had a 250 GB hard drive which I am replacing with two 500 GB HDs. I was thinking about going RAID 0 or RAID 1, or maybe just using the second HD for incremental backups. But somewhere deep in my mind a RAID 5 idea appeared. Do anybody of you use RAID 5 in your day-to-day computer? Is it worth it? How is performance? Supposedly, a bit better. What do you recommend?
Luis Alonso Ramos Intelectix Chihuahua, Mexico My Blog!
Luis, I installed a RAID5 configuration on my Q6600 box, 3x500GB drives. I did not think much of it until one of the drives failed. Once the drive removed and sent for repair, I was still able to turn on the computer and work in "degraded mode". Once the new drive came back, I installed it and it rebuilt. Now, what do I think about raid5 ? cheaper than RAID 1. Much better than RAID 0, actually, still wonder why they call that one "RAID". Regards JFG
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I will be reinstalling my main PC with Vista x64 this weekend. I took the opportunity to upgrade the RAM and the hard drives. It had a 250 GB hard drive which I am replacing with two 500 GB HDs. I was thinking about going RAID 0 or RAID 1, or maybe just using the second HD for incremental backups. But somewhere deep in my mind a RAID 5 idea appeared. Do anybody of you use RAID 5 in your day-to-day computer? Is it worth it? How is performance? Supposedly, a bit better. What do you recommend?
Luis Alonso Ramos Intelectix Chihuahua, Mexico My Blog!
If you are doing massive read/write operations or you require the highest level of redundancy of data you might want to consider RAID 5. If however you simply want to have a bit of improved speed for every day tasks/gaming you are not likely to notice any improvement by selecting RAID 5 over RAID 1. The cost benefit (purchasing extra hardware, extra power consumption, possibly needing larger power supply, configuration issues, etc) would likely come out in favor of a RAID 1 configuration. If you really need the extra throughput for read/write operations you should definitely consider a separate raid controller card or using a mainboard designed specifically as a server board unless you have CPU cycles to spare as the on board/bios based controllers do not totally offload the operations to the chipset. FWIW Dave
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Hello Gerardo, You bring up a good point: temperature. It's a desktop computer which currently has one HD, and if I put three in it, its fan might not be enough. What I wanted to do was something simple, and adding additional fans or power units is not simple :) I guess I am going to try RAID 5 with what I have right now, and depending on how it works, I'll keep it or go back to a single disk with one backup disk. Where are you from? What do you do? I see you are relatively new here, so welcome!! It's always nice to find someone from Mexico here :)
Luis Alonso Ramos Intelectix Chihuahua, Mexico Follow me on Twitter (@luisalonsoramos) or on my blog (www.luisalonsoramos.com)!
Hi Luis, Thanks for the warm welcome. Good luck on your trials! In fact, I've been a Code Project user for quite some time, however I'm not very active on the forums. I've found some excellent code here, and I'm really grateful to the community - I hope someday I can give something back that's really useful. :) I love programming and I'm totally into pattern recognition techniques. I work at Obsidian, a company me and some good friends formed a few years ago. We monitor TV and radio broadcasts with a software suite we developed in-house (that's why we need so much storage space). Are you also an entrepreneur at Intelectix? Cheers! :cool: Gerardo
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Hi Luis, Thanks for the warm welcome. Good luck on your trials! In fact, I've been a Code Project user for quite some time, however I'm not very active on the forums. I've found some excellent code here, and I'm really grateful to the community - I hope someday I can give something back that's really useful. :) I love programming and I'm totally into pattern recognition techniques. I work at Obsidian, a company me and some good friends formed a few years ago. We monitor TV and radio broadcasts with a software suite we developed in-house (that's why we need so much storage space). Are you also an entrepreneur at Intelectix? Cheers! :cool: Gerardo
I used to spend quite a lot of time in the forums, but recently I have not been as active as I would like. Sometimes there's just too much work, and other interests in life... I am sure you have much to contribute to CP. You just have yourself the time to start an article and you'll see it will come out by itself. Yeah, I started Intelectix around 5 years ago to provide quality custom software development here in Chihuahua. I found that there were a lot of freelancers that were not as reliable, and thus decided to start a seriuos company, that although small, could be reliable. We are still a small company (7 people), but we've had quite a lot of work recently. We do mainly .NET/SQL Server development, and have some interesting projects in our portfolio. Where are you? In Mexico City? :)
Luis Alonso Ramos Intelectix Chihuahua, Mexico Follow me on Twitter (@luisalonsoramos) or on my blog (www.luisalonsoramos.com)!