Is RAID 5 worth it?
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Luis Alonso Ramos wrote:
It would be a hardware controller already included with my motherboard.
No. Unless you paid $600 for the motherboard you do not have a hardware controller. This is a software controller and in windows that means performance is bad. http://thebs413.blogspot.com/2005/09/fake-raid-fraid-sucks-even-more-at.html[^]
John
modified on Tuesday, May 19, 2009 11:06 PM
My motherboard has the ICH9R chipset, which with a BIOS flash from here[^], can be made to support RAID 5 (It's a Dell Vostro 400). So, what that means is that the RAID support is done in the main CPU at software level (but not OS level)? I for sure didn't pay $600 for the motherboard, so you don't recommend it at all? Performance will be that bad?
Luis Alonso Ramos Intelectix Chihuahua, Mexico Follow me on Twitter (@luisalonsoramos) or on my blog (www.luisalonsoramos.com)!
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I haven't used Raid5 mainly due to cost. I did use RAID1 and performance was lousy - I mean REALLY lousy I mean MINUTES to boot. I think that was the MB controller / driver but gave up quite quickly trying to improve it. Instead I use the 2nd hard drive for daily backups, and an external drive for weekly backups (I'd use the external drive more often, but I can't get eSata drive to be hot-swappable) From the investigations I did when using RAID 1 I'd say teh controller and driver are more important that I had thought - and using the one on the MB might not be the best option. That said, it may be that someone who knew what they were doing would have been able to get it all working fine - but there's a distinct lack of step-by-step instruction available, many conflicting instructions, and lots of people with problems like I had.
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At work I have over 20TB of software raid 5 (or 6) on linux and only 1 TB on windows and the reason is cost. In linux software raid performance is good (or can be tuned to be good by extending the size of the stripe cache) where in windows software raid 5 performance sucks and you have no control of the cache. And thus I had to add a 3ware hardware controller in windows which ended up costing more than all the drives connected to it combined. They really need to fix their pricing structure..
John
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My motherboard has the ICH9R chipset, which with a BIOS flash from here[^], can be made to support RAID 5 (It's a Dell Vostro 400). So, what that means is that the RAID support is done in the main CPU at software level (but not OS level)? I for sure didn't pay $600 for the motherboard, so you don't recommend it at all? Performance will be that bad?
Luis Alonso Ramos Intelectix Chihuahua, Mexico Follow me on Twitter (@luisalonsoramos) or on my blog (www.luisalonsoramos.com)!
In my few weeks of testing last year I have found that bios/software/fake raid 1, 5 and 10 under windows XP was actually slower than a single hard drive (in reads and writes) in a 4 hard disk array case. I did this test a year ago with windows XP because I wanted to have each developer have improved performance with the addition of redundancy. After giving up on the test I ended up giving the developers single 750GB disks instead of a raid 5 array of 4x 500GB and instead adding the extra 500GB disks to my linux software raid 5 servers which were only going to get a few 750GBs.. It worked out fine until recently when my development has led me to very long compile times so I have on order a velociraptor while I wait for a 120GB SSD to cost less than $300 US.
John
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In my few weeks of testing last year I have found that bios/software/fake raid 1, 5 and 10 under windows XP was actually slower than a single hard drive (in reads and writes) in a 4 hard disk array case. I did this test a year ago with windows XP because I wanted to have each developer have improved performance with the addition of redundancy. After giving up on the test I ended up giving the developers single 750GB disks instead of a raid 5 array of 4x 500GB and instead adding the extra 500GB disks to my linux software raid 5 servers which were only going to get a few 750GBs.. It worked out fine until recently when my development has led me to very long compile times so I have on order a velociraptor while I wait for a 120GB SSD to cost less than $300 US.
John
Hi John, So I guess I'll go back to my original plan of two 500 GB HDs, using the second one to keep a daily backup of the first (for me 500 GB is more than enough). That's why I love this place!! Every time I have a question, someone who really knows about gives me a better answer than Google. Thanks!! :-D
Luis Alonso Ramos Intelectix Chihuahua, Mexico Follow me on Twitter (@luisalonsoramos) or on my blog (www.luisalonsoramos.com)!
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I agree - use backups for safety & raid for convenience or speed. Over the years I have seen two RAID systems fail. Both were setup to provide redundancy. Sure enough they provided redundant unrecoverable data. In one case the failure was in the controller, the other was a flaky cable giving bad data transfers. Having redundant HD's was a waste of HD space.
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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!
Do NOT use RAID5 on an nVidia motherboard - it is well known that their implementation can't be trusted. Perhaps they got it right now, but as of the 6 months old firmware it still wasn't working properly. Many other people have had the same experience as I. Do yourself a favor - if you decide to go against my advice, try "faking" a few failure scenarios and see what happens before you trust critical data with it. My nForce 680i board corrupted many files when a drive gave out...exactly what RAID5 is supposed to prevent. It's very easily reproducable...if I unplug a SATA connector from a live drive in system...system freezes (that's OK, although not ideal) and next boot, windows will yell about corrupted files...woohoo... nVidia seems to works well in drive pairs though (mirroring or striping). Just another reason to stick to Intel boards next time...
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Do NOT use RAID5 on an nVidia motherboard - it is well known that their implementation can't be trusted. Perhaps they got it right now, but as of the 6 months old firmware it still wasn't working properly. Many other people have had the same experience as I. Do yourself a favor - if you decide to go against my advice, try "faking" a few failure scenarios and see what happens before you trust critical data with it. My nForce 680i board corrupted many files when a drive gave out...exactly what RAID5 is supposed to prevent. It's very easily reproducable...if I unplug a SATA connector from a live drive in system...system freezes (that's OK, although not ideal) and next boot, windows will yell about corrupted files...woohoo... nVidia seems to works well in drive pairs though (mirroring or striping). Just another reason to stick to Intel boards next time...
Mike Marynowski wrote:
if you decide to go against my advice
Don't worry. I haven't received a single positive response on software RAID, so I will do what I thought originally: a second hard drive to daily backup the first one with incremental disk images or something like that. My motherboard (AFAIK) is Intel, but again, I might be wrong. Thanks for your suggestion :)
Luis Alonso Ramos Intelectix Chihuahua, Mexico Follow me on Twitter (@luisalonsoramos) or on my blog (www.luisalonsoramos.com)!
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Mike Marynowski wrote:
if you decide to go against my advice
Don't worry. I haven't received a single positive response on software RAID, so I will do what I thought originally: a second hard drive to daily backup the first one with incremental disk images or something like that. My motherboard (AFAIK) is Intel, but again, I might be wrong. Thanks for your suggestion :)
Luis Alonso Ramos Intelectix Chihuahua, Mexico Follow me on Twitter (@luisalonsoramos) or on my blog (www.luisalonsoramos.com)!
Integrated RAID on a motherboard is technically still "hardware" RAID. Software RAID is when you use Windows (or Linux) to manage a RAID array and it does the "logic" for you, instead of a hardware controller. If you are managing your array through Disk Management, its software RAID...if you have to go through a pre-boot BIOS-like interface or a vendor-specific software utility, it's hardware RAID.
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Integrated RAID on a motherboard is technically still "hardware" RAID. Software RAID is when you use Windows (or Linux) to manage a RAID array and it does the "logic" for you, instead of a hardware controller. If you are managing your array through Disk Management, its software RAID...if you have to go through a pre-boot BIOS-like interface or a vendor-specific software utility, it's hardware RAID.
Ok, what I have is hardware RAID integrated into the motherboard, but not with an independent RAID controller, but the main CPU doing it. According to John (in one of his posts above), its performance sucks in Windows OSs.
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!
i have done a couple of server with Intel ICH8/9/10 and i can tell you that mainly 9/10 are well worth it... intel has done a good job with this free raid... and also you can't compare this ICH RAID with Software RAID, and neither with hardware controllers... its right in the middle and above a lot of those entry level controllers that you buy... i bought an LSI last year it was a deception i prefer the ICH10 without any doubt... In my personal server i have an Tyan MB with ICH10 and 3x 750gb 7200rpm in RAID 5 and the throughput is around 200mb/s... even my system (Single) SCSI UW320 IBM 74gb 15000 rpm does not go past 74mb/s... Problems until today NONE... the only down its a little slow when checking data for curruption, but that just happens if the power fails or some like that... but you can continue to work at the same time... So i would say go for it... and if you want go for a MB from INTEL(INTEL MAKE AND MODEL NOT ASUS) with ICH10 they are real stable, and very good on performance...
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As the storage space increases it is worthwhile with a couple of caveats: 1. Don't use software (host PC) RAID5. Under any circumstances. 2. Limit the number of drives per array to four, at most five or the array rebuild time is too long. We have a NAS with three arrays, four drives each and our data survived a major water leak from the server room air conditioning system that dissolved the ceiling tiles until they gave way pouring an alkali solution that dissolved lumps of copper off the backplane PCBs. I wasn't very happy. :| Elaine (restrained fluffy tigress)
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on item #2 - note that rebuild times are inversely related to the number of drives. The more drives that you have, the quicker that you can rebuild one from parity. I think about it this way: if I have two drives, each is 1/2 of the data. If I have three, then 1/3. If four, 1/4, etc.
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Ok, what I have is hardware RAID integrated into the motherboard, but not with an independent RAID controller, but the main CPU doing it. According to John (in one of his posts above), its performance sucks in Windows OSs.
Luis Alonso Ramos Intelectix Chihuahua, Mexico Follow me on Twitter (@luisalonsoramos) or on my blog (www.luisalonsoramos.com)!
I think John probably had a buggy driver or something - Windows or not, the controller has to do the same thing. Integrated RAID controllers aren't much slower than cheap dedicated controllers, if at all - both offload XOR calculations to the processor, which means slower write times. You can expect a big boost in read performance though. So, I guess it depends what you are doing. RAID 1 will take a much smaller hit - you should get ALMOST the same read and write performance (EDIT: as a single disk). All my development machines are setup as RAID1. It takes me almost two days to configure a new machine, and I don't want to lose any local "work in progress" before it is backed up to the server. Throwing in a new drive and hitting "rebuild" is a lot easier than reconfiguring a machine from scratch for 20+ hours. The biggest problem with integated/cheap dedicated controllers is the lack of cache memory. Onboard cache will GREATLY increase your write performance since writes go into the high speed memory and get written to disk at a "better time" (idle, once it seeks to the right place, etc). An onboard dedicated XOR processor helps a bit, but any modern processor really doesn't have that much trouble computing 50MB/s of XOR data in the background, so it's not a big deal.
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i have done a couple of server with Intel ICH8/9/10 and i can tell you that mainly 9/10 are well worth it... intel has done a good job with this free raid... and also you can't compare this ICH RAID with Software RAID, and neither with hardware controllers... its right in the middle and above a lot of those entry level controllers that you buy... i bought an LSI last year it was a deception i prefer the ICH10 without any doubt... In my personal server i have an Tyan MB with ICH10 and 3x 750gb 7200rpm in RAID 5 and the throughput is around 200mb/s... even my system (Single) SCSI UW320 IBM 74gb 15000 rpm does not go past 74mb/s... Problems until today NONE... the only down its a little slow when checking data for curruption, but that just happens if the power fails or some like that... but you can continue to work at the same time... So i would say go for it... and if you want go for a MB from INTEL(INTEL MAKE AND MODEL NOT ASUS) with ICH10 they are real stable, and very good on performance...
Everyone else here has adviced me against integrated motherboard RAID. So, you think it can be worth it? Would I get better performance than a single drive? I like the redundancy, but I could as well solve that with daily backups. And RAID 0 I think would be a little dangerous.
Luis Alonso Ramos Intelectix Chihuahua, Mexico Follow me on Twitter (@luisalonsoramos) or on my blog (www.luisalonsoramos.com)!
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I think John probably had a buggy driver or something - Windows or not, the controller has to do the same thing. Integrated RAID controllers aren't much slower than cheap dedicated controllers, if at all - both offload XOR calculations to the processor, which means slower write times. You can expect a big boost in read performance though. So, I guess it depends what you are doing. RAID 1 will take a much smaller hit - you should get ALMOST the same read and write performance (EDIT: as a single disk). All my development machines are setup as RAID1. It takes me almost two days to configure a new machine, and I don't want to lose any local "work in progress" before it is backed up to the server. Throwing in a new drive and hitting "rebuild" is a lot easier than reconfiguring a machine from scratch for 20+ hours. The biggest problem with integated/cheap dedicated controllers is the lack of cache memory. Onboard cache will GREATLY increase your write performance since writes go into the high speed memory and get written to disk at a "better time" (idle, once it seeks to the right place, etc). An onboard dedicated XOR processor helps a bit, but any modern processor really doesn't have that much trouble computing 50MB/s of XOR data in the background, so it's not a big deal.
My idea of the RAID 5 is to get better performance with a little more reliability for a reasonable price. These days I am not doing much development, but still every now and then I do a few complicated SQL queries or builds that take a couple of minutes. So, after a few hours here in CP (and simultaneously in Google) I have learned quite a few things, but still cannot make my mind on whether to go RAID 5 or just a single drive with a daily backup to a second drive. :confused:
Luis Alonso Ramos Intelectix Chihuahua, Mexico Follow me on Twitter (@luisalonsoramos) or on my blog (www.luisalonsoramos.com)!
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Hi John, So I guess I'll go back to my original plan of two 500 GB HDs, using the second one to keep a daily backup of the first (for me 500 GB is more than enough). That's why I love this place!! Every time I have a question, someone who really knows about gives me a better answer than Google. Thanks!! :-D
Luis Alonso Ramos Intelectix Chihuahua, Mexico Follow me on Twitter (@luisalonsoramos) or on my blog (www.luisalonsoramos.com)!
In my experience RAID5 is not worth having if its implemented in software under Windows, too slow. I use a 146G Seagate Cheetah as my system drive. I keep data on two 500G Seagate Barracudas which are striped and I have a similar drive housed externally onto which I do hourly selective incremental backups I'm feel more secure with this arrangement than I did with a 3 disk software Raid 5 array, and I get better performance.
Multi famam, conscientiam pauci verentur.(Pliny)
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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!
Tried to build it twice, both times gave up due to controller and disk problems. According to what I learned on the internet: 3 disks doesn't work very well - performance wise and other. Someone (who seemed to work with it a lot) said something about "at least 5 disks". Also, RAID controllers still seem to insist on rebuilding the entire disk when it fails once. However, relative failure rates haven't gone down at the same speed capacities have gone up, so with todays amounts of data, rebuilds happen much more frequent. Also, multiple disk fails aren't that unlikely (compared to single disk fails). The most prominent reason is a failing power supply. Due to all of this, I ended up using a software(!) RAID 0 coupled with a daily robocopy to an external disk with its own power supply. It isn't that much of a racer, but keeps a system on older disks (2x 80GB SAMSUNG) build time competetive with some of the newer machines around. I haven't run into any (obvious) problems with data loss yet. (not the newest though - building on 4 cores 15 minutes for both configurations. I am jealous!)
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Do NOT use RAID5 on an nVidia motherboard - it is well known that their implementation can't be trusted. Perhaps they got it right now, but as of the 6 months old firmware it still wasn't working properly. Many other people have had the same experience as I. Do yourself a favor - if you decide to go against my advice, try "faking" a few failure scenarios and see what happens before you trust critical data with it. My nForce 680i board corrupted many files when a drive gave out...exactly what RAID5 is supposed to prevent. It's very easily reproducable...if I unplug a SATA connector from a live drive in system...system freezes (that's OK, although not ideal) and next boot, windows will yell about corrupted files...woohoo... nVidia seems to works well in drive pairs though (mirroring or striping). Just another reason to stick to Intel boards next time...
I second that NVIDIA Mobo's and RAID do not go together. I had a system with 4 raided raptors which should have been lightning fast. It was only marginally faster than a single drive bu8t Vista (Grrrrr) would fail completly every 3 months or so. The Mobo was a rather expensive one as well. The system runs perfectly now with Win7 and a single 500GB drive. Raptors went on fleabay. :laugh:
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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!
Thought RAID 5 was 3 or more disks - so if you have two it wouldn't apply! i.e RAID 0 or 1 available (?) RAID 0 For speed and suicide jocks only i.e. gamers! RAID 1 More reliable in that if one goes down you can continue but loose half your capacity and you still need to backup (burnt or stolen computer etc) For development/general machines I don't bother with raid - just backup to external drives For Web Servers use RAID 1 (with hardware controller) - this means if one drive fails system will continue (don't like having to get up early!). Backup still required of course :)
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HDs are so cheap these days that I'll just get one more to give RAID 5 a try. Thanks!
Luis Alonso Ramos Intelectix Chihuahua, Mexico My Blog!
You need at least 3 drives for a RAID-5, but, as the mighty tigress has stated, better get 4, so you have at least one replacement in stock. Just saying.
Cheers, Sebastian -- "If it was two men, the non-driver would have challenged the driver to simply crash through the gates. The macho image thing, you know." - Marc Clifton
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Everyone else here has adviced me against integrated motherboard RAID. So, you think it can be worth it? Would I get better performance than a single drive? I like the redundancy, but I could as well solve that with daily backups. And RAID 0 I think would be a little dangerous.
Luis Alonso Ramos Intelectix Chihuahua, Mexico Follow me on Twitter (@luisalonsoramos) or on my blog (www.luisalonsoramos.com)!
if you want a faster and reliable system you go with RAID 5 3 hdd is OK and it works just fine... if you want just the redundancy go with raid 1 but no performance gain... if you want just the performance go with raid 0, but your risks double... as if one the hdd goes bad you loose information of both... intel ICH configuration has only 4 or 5 options on the menu... i dont know how some people can have problems... its a straight process... you chose the hdd's and raid type then you create the volume exit and its done... To enter the config you press CTRL+I on boot when it shows on the screen. dont forget if you are using 2003 server or xp you may have to use the driver disk to add the raid controller driver to windows setup so it recognizes the drive. on vista you dont have this problem it comes with the driver already... After intalling windows you can install Intel® Matrix Storage Manager it gives you all the info... and also alerts you and shows the status of the hdd's and raid as when rebuild... About the backups, having redundancy doesn't avoid Backups... You should do backups anyway... the intention is UPTIME and RELIABILITY not avoid backups.... maybe you can change your backup policy a lit but continue making backups from time to time... you can have some kind of power issues that burn all your hdd and if you dont have backup you are in trouble...