How much would you pay for a SW only RAID-5?

[velis]

I for one don't want a true HW controller, but a good SW solution that provides what RAID-5 provides with maybe a bit lower performance. The upside is surely at least lower power consumption and price (no card to speak of). I really don't think today's desktop processors have issues providing the speed I want... Not to mention all those MB integrated RAID controllers are actually all software anyway.

So, am I the only one?
Are there any other poor souls out there struggling to get something as simple as SW RAID-5, but their MB chips suck badly and their Windows 7 doesn't support even a hackable way of doing it?

Thanks for your thoughts,
Jure

 

[Emulex]

no kidding my dell inspiron has ich9r raid-5. it sucks because its SOFTWARE based.

Raid 5/6 require the Battery/FLASH backed write cache for so much data in flight and the double read/write penalty. raid-10 makes far more sense since it doesn't incur many of the penalties and the cost at low count is near equal to raid-6.

raid-1E is an interesting variance (odd drive raid-10) too.

nothing cheap is good

 

[greenhawk]

a good SW solution that provides what RAID-5 provides with maybe a bit lower performance.

nice idea but depending on the implementation, basic software can be worse than motherboard raid. The last pure non-OS raid I used was on a silicon image controller, and it used Java as the language for the raid 5. that was so bad as to get pulled pretty quicky (even with a q6600 driving it).

As to better power, VS a motherboard implementation, power is in the same ball park. VS a good hardware raid, power should be a little lower I suspect as good dedicated hardware is nearly always better than the same in software.

So, am I the only one?

no, but when you look into software vs hardware raid, some things stand out as rather important issues that some people over look.

The only good software raid is generally OS based ones. As such, it does place a restriction on changing the array. Linux is better, but windows needs a backup - distroy - copy back apprach to upgrading.

so from $0 to hardware is a large step when wanting either
-speed
-portability (to some extent)
-expandability
-types of raid

When looking at costs though, even if someone did want to pay for something that was good enough to work, it would have to be lower than linux or windows (raid supported verision).

 

[wirednuts]

i remember "hacking" winxp to allow software raid 5... was nice..

 

[Rifter]

I would pay nothing, i ran SW raid 5 for 3 years on my ubuntu home server and it cost me nothing.

 

[corkyg]

HW is generally more reliable, and can more easily be transferred from one machine to another.

 

[Rifter]

HW is generally more reliable, and can more easily be transferred from one machine to another.

This will totally depend on the software. I upgrade my server from a socket 939 system to a AM2+ system and kept my same ubuntu install and raid array intact and it worked fine. I did of course have backups just incase it didnt turn out so well.

 

[velis]

Interesting. Even though you are all talking about how bad SW solutions can be.
I was assuming that the fictional SW solution we're talking about would be good and feature rich. As good and feature rich as any HW controller out there. Sans battery backup, of course.

 

[Absolution75]

Its pretty hard to find a chipset that doesn't run raid 5 these days. Sure, you can get the really low end stuff that doesn't have it - but any board > $80 seems to just have it.

Its not as bad as people think/say. I've been running raid-5 on ich10r for about a year now. Though I'll probably upgrade to a HW raid controller soon as they are only like $50.

 

[dac7nco]

OP, you're perpetuating the idea that people should/can RAID-5 across at minimum three 3TB "green" discs... which should be discouraged. This forum has ceased to be those who know what's up - to being: where's my data?!

Daimon

 

[velis]

OP, you're perpetuating the idea that people should/can RAID-5 across at minimum three 3TB "green" discs... which should be discouraged.

I don't get it. So you're saying people should not RAID the 3TB green disks? AFAIK this can't be done reliably with HW controllers (drives keep dropping out of the array), which makes a SW solution al the more desirable. Especially because these drives don't exactly tend to break every other day themselves.

So why should this practice be discouraged? I want to practice exactly this scenario...

This forum has ceased to be those who know what's up - to being: where's my data?!

I'm assuming this means AT readers know what they are doing and that means no-no to SW RAID since it's unreliable?
Even if I got this right I still don't know why you (they) would think that. After all, even HW controllers are SW (firmware) in the end...

I'll probably upgrade to a HW raid controller soon as they are only like $50.

Can you name / link such a controller? I can't seem to find any under $400 over here. It seems you're talking about Promise which are SW controllers...

 

[alaricljs]

Because RAID 5 at this point should not be used. Raid 6 or something even more redundant or you risk the failure of another drive during the rebuild. It's nearly guaranteed by the math, although of course in reality it's much less frequent than that.

 

[VirtualLarry]

The last pure non-OS raid I used was on a silicon image controller, and it used Java as the language for the raid 5.

The Silicon Image controllers, use Java for the "Raid management GUI" app, but the drivers themselves (written in native code, not Java) are responsible for the XOR calculations for RAID 5.

 

[Absolution75]

Can you name / link such a controller? I can't seem to find any under $400 over here. It seems you're talking about Promise which are SW controllers...

http://www.overclock.net/raid-controllers-software/359025-perc-5-i-raid-card-tips.html

 

[dac7nco]

I don't get it. So you're saying people should not RAID the 3TB green disks? AFAIK this can't be done reliably with HW controllers (drives keep dropping out of the array), which makes a SW solution al the more desirable. Especially because these drives don't exactly tend to break every other day themselves.

Sorry for the harsh post, OP. RAID-5 is an obsolete system which shouldn't be used with gigantic discs, due to the HUGE risk of a second disc dropping out of the array while rebuilding... that is assuming you swap the first failed disc immediately, and are not... 1: at work an hour away in SF... 2:at a bar... 3: sleeping. SATA technology has brought us to the point where RAID-5 is cheap and easy... huge disc capacities, and questionable quality have made that irrelevant. RAID-1, 10, 6 or 60 are the best I could recommend.

You will save a lot of money and gray hair if you use a 3TB disc as an active read/write platform for your recent stuff, and a backup platform (RAID-1/10/6...) as a backup that only spins up once a month.

Remember, that hardware RAID solutions are transportable between systems as you upgrade. Software RAID managed by the operating system or IOH has you permanently using that old system as a server, until you invest the same amount of cash you could've spent on a hardware RAID controller into spare discs.

Daimon

 

[alaricljs]

Remember, that hardware RAID solutions are transportable between systems as you upgrade. Software RAID managed by the operating system or IOH has you permanently using that old system as a server, until you invest the same amount of cash you could've spent on a hardware RAID controller into spare discs.

Unless you use just about any unix based SW raid setup. I can move my disks to any other linux box without issues. On the other hand my RAID setup is old enough that I couldn't get the same HW controller to replace a failed one should it happen now. That would mean losing all my data if it wasn't backed up.

I don't know about the FreeBSD or Solaris options like Nexenta and so on, but I'd be amazed if you couldn't just connect the drives to the new system and get it up and running without any real issues.

 

[dac7nco]

Unless you use just about any unix based SW raid setup. I can move my disks to any other linux box without issues. On the other hand my RAID setup is old enough that I couldn't get the same HW controller to replace a failed one should it happen now. That would mean losing all my data if it wasn't backed up.

I don't know about the FreeBSD or Solaris options like Nexenta and so on, but I'd be amazed if you couldn't just connect the drives to the new system and get it up and running without any real issues.

LOL, I should have written a "however"; I've used ZFS on occasion, which when paired with ECC memory and a UPS makes HW RAID controllers irrelevant.

Nice post!

Daimon

 

[velis]

This makes much more sense now. Though I must say I'm not exactly fond of getting only 50% of my capacity and even less likely to even be able to set up a raid 6 array. For any decent percentages I'd need a 6 drive array to get where I can be with 3 drives using RAID-5 (and I find 1/3 quite wasteful).
Only high end motherboards sport 8 sata ports (6 for array, 1 for system drive + one for DVD / BR).
Also I'd love to get something that would spin up once a month for backup only, but 4 bay enclosures also cost quite a lot, not to mention they are usually quite limited (capacity - wise). For this purpose I now just use 1TB 2.5 USB drives. They fit the bill just nice.

Finally, I must say I didn't expect such a negative response from AT members. Google is full of hits for SW RAID-5 under Vista / 7. I really expected more people would be in favor or at least sympathetic with a SW solution on Windows.

And I'm not talking about an OS provided solution either - MS is obviously not inclined to enable RAID-5 or introduce RAID-6 as a OS feature for client OS versions. What I want is a working solution that survives OS or motherboard upgrades - something to install in addition to the OS... That's the kind of SW solution I'd like. Possibly even portable in case I ever decided that Windows doesn't cut it any more...

 

[Rebel44]

I would love to be able to buy something like Unraid that would work inside Win7.

I dont care if its SW or HW if it works.

 

[dac7nco]

This makes much more sense now. Though I must say I'm not exactly fond of getting only 50% of my capacity and even less likely to even be able to set up a raid 6 array. For any decent percentages I'd need a 6 drive array to get where I can be with 3 drives using RAID-5 (and I find 1/3 quite wasteful).
Only high end motherboards sport 8 sata ports (6 for array, 1 for system drive + one for DVD / BR).
Also I'd love to get something that would spin up once a month for backup only, but 4 bay enclosures also cost quite a lot, not to mention they are usually quite limited (capacity - wise). For this purpose I now just use 1TB 2.5 USB drives. They fit the bill just nice.

Finally, I must say I didn't expect such a negative response from AT members. Google is full of hits for SW RAID-5 under Vista / 7. I really expected more people would be in favor or at least sympathetic with a SW solution on Windows.

And I'm not talking about an OS provided solution either - MS is obviously not inclined to enable RAID-5 or introduce RAID-6 as a OS feature for client OS versions. What I want is a working solution that survives OS or motherboard upgrades - something to install in addition to the OS... That's the kind of SW solution I'd like. Possibly even portable in case I ever decided that Windows doesn't cut it any more...

It's called the Law of diminishing returns, and your math is addled. A six-disc RAID-6 would be 2/3ds capacity. Using six 3TB Ultrastars, you would have 12TB capacity. Using RAID-5, you would have 15... you don't realize how fragile spinning platters are until you start RAIDCing them. Back in the day, with a RAID-5 of three 207MB SCSI discs, it was the recently invented shiznit, with more I/O than you could get with individual discs. RAID was designed for uptime, not data security. with Terabytes of .H264, you want security, not speed. Spinning six multi-platter discs more than you have to is a bad, bad idea.

I use a QNAP NAS with eight 3TB discs in RAID-6 (~18TB). The house machines have a 3TB disc each, which are updated on a monthly schedule, and user data is backed up to each other and the NAS monthly. Spinning up the NAS arbitrarily is not an option... reliable RAID costs moolah.

Daimon

 

[greenhawk]

The Silicon Image controllers, use Java for the "Raid management GUI" app, but the drivers themselves (written in native code, not Java) are responsible for the XOR calculations for RAID 5.

for what ever the reason, for me the drive array was not visable to windows without the GUI open. Given the performance of, IIRC, about 10MB/s at peak speeds, then the implementation was crap no mater how it was dressed.

 

[greenhawk]

Finally, I must say I didn't expect such a negative response from AT members. Google is full of hits for SW RAID-5 under Vista / 7. I really expected more people would be in favor or at least sympathetic with a SW solution on Windows.

Proberly too many people in the group of "been their, done that, and have the burnt fingers to prove it".

Personally, the disadvantages of software raid 5 for most soho consumer grade gear (ie: cheap), makes it a waste of resources.

There is one that looks promising to me, but then it is more of a snapshot raid implementation. Lots of advantages over raid 5, espically for non-changing data (which mine is). Just have not the time or resouces to set it up currently.

 

[HappyCracker]

I deal with enterprise class storage arrays day in and day out. What we're hearing from the vendor is, any drive over 500GB should probably have a dual-parity RAID like R6. That's not to say you couldn't run R5 and have no problems upon rebuilds, but as drives get larger, rebuild times extend. Personally, I run R1 at home and have seen rebuilds on 1.5TB drives in the span of hours and not days, thus minimizing my exposure window. To echo Emulex's statement above, anything like R1/R10 doesn't have the same penalty for writes as R5/R6, and is generally recommended for best performance unless you have a good hardware controller. For all of our enterprise applications, we run R5 because the array is cache-rich and lots of hardware to deal with the XOR calculations. But at home, I'm ghetto fabulous. I may not always run RAID 5, but when I do, it's on a hardware controller.

 

[Cerb]

Finally, I must say I didn't expect such a negative response from AT members. Google is full of hits for SW RAID-5 under Vista / 7. I really expected more people would be in favor or at least sympathetic with a SW solution on Windows.

And I'm not talking about an OS provided solution either - MS is obviously not inclined to enable RAID-5 or introduce RAID-6 as a OS feature for client OS versions. What I want is a working solution that survives OS or motherboard upgrades - something to install in addition to the OS... That's the kind of SW solution I'd like. Possibly even portable in case I ever decided that Windows doesn't cut it any more...

I'm about to reinstall Windows on a non-bootable SW RAID 1. Disk diags and chkdsk all come out clean, and used/free matches, to the byte. Just won't boot. Oh, it tries, but it fails. I can find others with exactly the same symptoms, through Google. I've tried everything I could think of, and everything all of them tried. No dice. I've never had that happen with OS RAID, nor real HW RAID. I have lost an entire array with OS RAID 5, though, due largely to the lack of write caching.

It should be done through software, but with the FS managing the array, maintaining transactional integrity at the FS level, rather than the array and FS working independently, which can allow small errors in the array to become disastrous errors for your FS.