Is RAID 5 worth it?
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It would be a hardware controller already included with my motherboard. And I am thinking 3 HDs (my computer won't allow for more without adding an additional SATA controller card). So, would you do it?
Luis Alonso Ramos Intelectix Chihuahua, Mexico My Blog!
Yes, it is worth looking at drives which are relatively new since any failures may not be for quite a while and you want to be able to buy a replacement if needed. You will also get some acceleration over a single drive too.
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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!
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Yes, it is worth looking at drives which are relatively new since any failures may not be for quite a while and you want to be able to buy a replacement if needed. You will also get some acceleration over a single drive too.
Visit http://www.notreadytogiveup.com/[^] and do something special today.
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!
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There is some optimisation which probably comes with experience.
Visit http://www.notreadytogiveup.com/[^] and do something special today.
Yeah - I really needed a 2nd PC to be able to experiment on without risk to my live data! When you get messages telling you al the data on the disk may be destroyed, it kinda makes you nervous (even though I had two backups)
___________________________________________ .\\axxx (That's an 'M')
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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 a RAID5 NAS next to me. performance is fine, for what i use it for: storage of media. i don't do any development directly on it.
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It would be a hardware controller already included with my motherboard. And I am thinking 3 HDs (my computer won't allow for more without adding an additional SATA controller card). So, would you do it?
Luis Alonso Ramos Intelectix Chihuahua, Mexico My Blog!
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
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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)
Visit http://www.notreadytogiveup.com/[^] and do something special today.
Trollslayer wrote:
Don't use software (host PC) RAID5. Under any circumstances.
Only in windows. In linux (at work) I have 6 drive SATA linux software raid5 arrays that net over 200 MB/s writes and over 300MB/s reads. Not too shabby. With the same exact hardware on windows XP I got less than single disk speed for raid 1, 5 and 10. It seems that software wise raid under windows is very broken. I understand the reason however. In linux there is a cache of the stripes that is user adjustable. In windows this cache either does not exist or is way too small so it hampers performance to an enormous extent. One reason for setting this cache to be small is that if the power went off you loose everything in cache and if the cache was directory structure you could potentially loose more than the just the files that are open. This is why hardware controllers have battery backup. I solve this issue in linux by having a dedicated UPS attached to every single server. Some will catch that this does not take care of the case if the operating system crashed. In linux this is a very rare occasion that I see less then 1 time per 5 years per machine and I do have backups.
John
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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.
___________________________________________ .\\axxx (That's an 'M')
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.
Melting Away www.deals-house.com www.innovative--concepts.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!
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)
Visit http://www.notreadytogiveup.com/[^] and do something special today.
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)!