I'm interested in having RAID in an upcoming build. I want to have some kind of redundancy. This computer will mostly be for gaming.I just can't decide what type to get. I don't want RAID 0 because it has no redundancy. I don't want 1 because there is a lot of wasted disk space. There is a lot of wasted disk space with raid 10, too. My last option is raid 5. Raid 5 seems right for me, but I have heard that there is slow write speeds. What should I do? Should I go for an expansion card, or could I stick with the onboard controller? Would it be a good idea to put my OS on a raid 5 array? Thanks.
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Need Help With RAID.
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Dangman
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It would not be a good idea to keep your OS on the RAID 5 array. You want to keep the OS separate of the RAID 5 array in case anything happens to the array or the OS drive.
RAID 5 has slow write speeds only if you use software RAID (that includes using the mobo's onboard RAID). If you use a hardware RAID controller, then you'll have good write speeds with RAID 5. Though I've heard that Linux MDADM software RAID has pretty decent write speeds (way better than onboard RAID or windows based apparently)
RAID 5 has slow write speeds only if you use software RAID (that includes using the mobo's onboard RAID). If you use a hardware RAID controller, then you'll have good write speeds with RAID 5. Though I've heard that Linux MDADM software RAID has pretty decent write speeds (way better than onboard RAID or windows based apparently)
Where should I put my OS on, if I don't put it on the RAID array?
If I get a Hardware RAID controller, I don't want to spend a lot of money on it. What controller would you recommend?
Dangman
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If you want uptime, then put the OS on a RAID 1 array. If uptime isn't needed, then keep the OS on a separate drive.
True hardware controllers are bit expensive. Minimum is $300. Check the usual suspects, Adaptec, Areca, Highpoint, etc.
That much for a controller! Even for a simple 4 port one?
Dangman
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Yup, even for a simple 4 port one, it's gonna be $300 minimum for a new one.
I don't really have the money for that. Do I have any other options?
Dangman
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Yeah, use the onboard RAID and deal with the CPU usage and relatively low write speeds.
EDIT:
Or switch to Linux for better software RAID performance.
how much load will onboard RAID put on the CPU( I'm getting the i7 930)? When you say low write speeds, how low do you mean?
Dangman
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The speeds and the load varies depending on the drives and the size of array. But I've heard and seen for CPU usage ranging from 10% to 50% at all times. As for write speeds, around 15MB/s to 40MB/s.
That's worse than I thought. Should I ditch RAID altogether?
Dangman
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Well RAID 5 at the very least if the performance isn't up to your needs.
then what type do you recommend?
Dangman
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If you regularly back up your files and if you need sheer performance, RAID 0 for the OS.
If you regularly back up your files and if you need uptime for the OS drive, RAID 1 for the OS.
Note that RAID IS NOT BACKUP. So no matter what RAID type you go with, make sure that you have a backup/copy of your critical and irreplaceable files somewhere else like an external hard drive, NAS, file server, DVD/blu-ray, online storage, etc.
I think I'm leaning towards 0, but how are drive failure rates for current drives?
Dangman
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Dunno about current drive failure rates. Obviously not high. But should be low as long as the drives were packaged and shipped correctly, used with a good PSU, and kept relatively cool.
I heard that some drives don't work with RAID. do you know if these do? http://www.newegg.com/Product/Product.aspx?Item=N82E16822148433
thanks. I'll use those
InvisiBill
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You started the thread stating that you wanted RAID for redundancy. Now you've ended up at RAID0, which provides no redundancy and only performance (noticeable for only certain types of operations really). Since one drive failure with RAID0 loses two disks' worth of data, it actually decreases reliability.
RAID0 on my old KT7A-RAID system did load huge EverQuest zones noticeably faster than my girl's otherwise comparable system. In "regular app" performance though, there wasn't any difference. RAID0 doesn't help the latency of a HDD at all, so small accesses won't really benefit from it. Reading or writing huge sequential files, you'll be able to split the load over two drives and get much better performance.
If you want cheap and simple, RAID1 provides a backup copy of your drive. If you want more efficient use of space, RAID5 uses parity to ensure data integrity, as opposed to simply making another copy. Note that RAID5 requires at least three disks, and either a good controller or a lot of CPU load as others have stated. Any RAID setup will also add complexity to your system. It might be as simple as supplying a driver during the OS install, but it might cause additional headaches down the road if there are issues.
And in case you missed it before, RAID is not backup. RAID is designed to help uptime, not to act as a backup solution. With RAID1, you do have a backup copy in case of physical failure of a drive. However, you don't have protection from accidental deletion, viruses, complete PC failure (like the PSU dying and taking out both drives), etc. If you don't have a backup solution already, you'd probably be better off using a single drive for your PC, and a second drive as a backup destination. You could have it internal and use one of the many backup apps to make copies of your data to. It would be better to have it external, so that major PC hardware failure didn't kill the backup too. Putting it in a separate system (WHS, FreeNAS, OpenFiler, etc.) would completely isolate it from problems with your main PC.
P.S. RAID is not backup
RAID0 on my old KT7A-RAID system did load huge EverQuest zones noticeably faster than my girl's otherwise comparable system. In "regular app" performance though, there wasn't any difference. RAID0 doesn't help the latency of a HDD at all, so small accesses won't really benefit from it. Reading or writing huge sequential files, you'll be able to split the load over two drives and get much better performance.
If you want cheap and simple, RAID1 provides a backup copy of your drive. If you want more efficient use of space, RAID5 uses parity to ensure data integrity, as opposed to simply making another copy. Note that RAID5 requires at least three disks, and either a good controller or a lot of CPU load as others have stated. Any RAID setup will also add complexity to your system. It might be as simple as supplying a driver during the OS install, but it might cause additional headaches down the road if there are issues.
And in case you missed it before, RAID is not backup. RAID is designed to help uptime, not to act as a backup solution. With RAID1, you do have a backup copy in case of physical failure of a drive. However, you don't have protection from accidental deletion, viruses, complete PC failure (like the PSU dying and taking out both drives), etc. If you don't have a backup solution already, you'd probably be better off using a single drive for your PC, and a second drive as a backup destination. You could have it internal and use one of the many backup apps to make copies of your data to. It would be better to have it external, so that major PC hardware failure didn't kill the backup too. Putting it in a separate system (WHS, FreeNAS, OpenFiler, etc.) would completely isolate it from problems with your main PC.
P.S. RAID is not backup
I am already have a backup for my system. I am aware that raid is not a backup, But if drive failures are not likely, then I think raid 0 should be fine.
Dangman
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Just want to be clear: I said that the likelihood of drive failure is relatively low depending on various conditions. So drive failure is still likely possible but varies from low to high depending on various conditions (including luck)
Using RAID0 + backup is fine, as long as the backup is of high quality.
I would even think most RAID0s on windows fail with the disks themselves being fine. So disk failure is not the biggest danger of running a RAID0; the RAID layer itself can fail; and that happens with RAID1/5 too. To have a good backup that's separate from everything is really protecting yourself; something RAID never can especially the poor driverRAID offered on Windows.
I would even think most RAID0s on windows fail with the disks themselves being fine. So disk failure is not the biggest danger of running a RAID0; the RAID layer itself can fail; and that happens with RAID1/5 too. To have a good backup that's separate from everything is really protecting yourself; something RAID never can especially the poor driverRAID offered on Windows.