What's the first thing you do when you get a new laptop or system?
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Remember that RAID cards are slower when you go to hardware RAID compared to software RAID. But we use them because it offloads processing from the main CPU and because of convenience. But we never do it for speed.
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@scottalanmiller said:
Remember that RAID cards are slower when you go to hardware RAID compared to software RAID. But we use them because it offloads processing from the main CPU and because of convenience. But we never do it for speed.
Why are hardware RAIDs slower than software? One uses the (I hope) specially designed processor for this task, the other uses the CPU.
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@Dashrender said:
Why are hardware RAIDs slower than software? One uses the (I hope) specially designed processor for this task, the other uses the CPU.
Because the central CPU is just SO much faster. Even a specially designed $50 processor can't keep up with that $800 Xeon that is powering the main system.
Software RAID became almost universally faster around 2001 when the Pentium III became the standard entry point server processor.
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So why haven't we moved to that solution on Intel based systems? Would we see so little gain? Or would this require a fundamental change for the system board makers to make hot swappable plugs? OR are the big vendors holding us back because of the prices they get to charge us for RAID cards?
If Software really is faster - why not go that way unless there are other things holding us back that either make it more expensive or impossible to do?
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@Dashrender said:
So why haven't we moved to that solution on Intel based systems? Would we see so little gain?
Because, like nearly everything in SMB IT, performance is not a key issue. If we were concerned about performance as the primary factor we would not be using AMD64 processors at all, we'd run nothing but UNIX, on software RAID, etc.
We run Windows, AMD64 chips and hardware RAID because they are easy, convenient and protect us. There is almost no major decision made in SMB IT (or even enterprise IT) where performance is the driving factor. A secondary or tertiary one maybe, but not a driving one.
Software RAID is the only option on big iron servers and always has been. Hardware RAID only exists because of deficiencies in how the SMB world handles software RAID (Windows SR is terrible, VMware doesn't have it, etc.)
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@Dashrender said:
Would we see so little gain?
Extremely little. The only place you'd really see it is on RAID 6 and 7 systems, RAID 7 is software RAID only already so that point is moot.
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@Dashrender said:
Or would this require a fundamental change for the system board makers to make hot swappable plugs? OR are the big vendors holding us back because of the prices they get to charge us for RAID cards?
They are all hot swappable already and have been for as long as I've been aware. You can go to MDADM, Windows SR or ZFS today and you have had hot swap since the 1990s at least.
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@Dashrender said:
If Software really is faster - why not go that way unless there are other things holding us back that either make it more expensive or impossible to do?
Because outside of the most extreme cases, speed just isn't that important. And when it is, the truly high speed systems like FusionIO can't use hardware RAID anyway.
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Same reasons that we don't tune our filesystems for the absolute fastest performance. NTFS isn't the fastest FS out there, but it is fast enough. The differences just are not that important 99.999% of the time.
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@scottalanmiller said:
Because, like nearly everything in SMB IT, performance is not a key issue.
That right there is the god damn truth. It shocked me for a second to see it in black and white but, damn it, it's true.
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OK so speed isn't a driver, but cost often is - wouldn't our systems be less expensive if we dumped the RAID controller? or because Windows is so bad at SR the cost of the controller is worth while?
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@Dashrender said:
or because Windows is so bad at SR the cost of the controller is worth while?
Well if the point is to protect your data ......
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@Dashrender said:
OK so speed isn't a driver, but cost often is - wouldn't our systems be less expensive if we dumped the RAID controller?
Cost isn't a primary driver either or, again, we wouldn't be using Windows, right? Windows is like hardware RAID.... pay more, get less.... except it comes with some "ease of use" features that tend to pay off.
Hardware RAID is super simple when you need to deal with separation of duties or blind swap (datacenter swapping without system admin interaction.) Hardware RAID is "idiot proof" allowing IT pros who don't know how their systems work or don't even know what is running there to do drive swaps based on blinking lights alone. In fact, it makes it so easy, that drive replacement is no longer an IT task but a bench task. No computer knowledge needed. See a yellow light, replace with a matching part. Don't even need to know that it's a computer you are working on.
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@scottalanmiller said:
@Dashrender said:
or because Windows is so bad at SR the cost of the controller is worth while?
Well if the point is to protect your data ......
So that's it - Windows is so bad at SR our data is safer in hardware RAID... I wonder why MS doesn't fix this? Wouldn't customers end up better off? I'm guessing the effort just wouldn't pay off for them?
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@scottalanmiller said:
@Dashrender said:
OK so speed isn't a driver, but cost often is - wouldn't our systems be less expensive if we dumped the RAID controller?
Cost isn't a primary driver either or, again, we wouldn't be using Windows, right? Windows is like hardware RAID.... pay more, get less.... except it comes with some "ease of use" features that tend to pay off.
Hardware RAID is super simple when you need to deal with separation of duties or blind swap (datacenter swapping without system admin interaction.) Hardware RAID is "idiot proof" allowing IT pros who don't know how their systems work or don't even know what is running there to do drive swaps based on blinking lights alone. In fact, it makes it so easy, that drive replacement is no longer an IT task but a bench task. No computer knowledge needed. See a yellow light, replace with a matching part. Don't even need to know that it's a computer you are working on.
I take it software can't or doesn't work like this?
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@Dashrender said:
So that's it - Windows is so bad at SR our data is safer in hardware RAID... I wonder why MS doesn't fix this? Wouldn't customers end up better off? I'm guessing the effort just wouldn't pay off for them?
They are finally addressing it down, it's called Storage Spaces. But only time will tell if it is enough. And you'd still have the blind swap issue. People who run Windows rarely know enough about storage to safely handle non-blind swap systems.
Think about moving to software RAID in your shop. Sure when you implement it today you know what to do. But what about the guy that replaces you or when you call the vendor for a drive replacement . With software RAID the vendor needs you to be involved in a drive swap, they can't do it without you.
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@Dashrender said:
@scottalanmiller said:
@Dashrender said:
OK so speed isn't a driver, but cost often is - wouldn't our systems be less expensive if we dumped the RAID controller?
Cost isn't a primary driver either or, again, we wouldn't be using Windows, right? Windows is like hardware RAID.... pay more, get less.... except it comes with some "ease of use" features that tend to pay off.
Hardware RAID is super simple when you need to deal with separation of duties or blind swap (datacenter swapping without system admin interaction.) Hardware RAID is "idiot proof" allowing IT pros who don't know how their systems work or don't even know what is running there to do drive swaps based on blinking lights alone. In fact, it makes it so easy, that drive replacement is no longer an IT task but a bench task. No computer knowledge needed. See a yellow light, replace with a matching part. Don't even need to know that it's a computer you are working on.
I take it software can't or doesn't work like this?
It could, but realistically does not. It requires intervention on the system side. Still hot swap, nothing gets powered down, but it isn't completely transparent.
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Same as @MattSpeller . I nuke the provided Windows, recovery partition, etc and install vanilla Windows.
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Intel doesn't make their own servers, they make AMD64 clones (or IA64 which are all Intel, but those effectively died out many years ago, no one is buying Itanium anywhere, let alone in the SMB.) AMD64 is essentially the only architecture that exists in the SMB market until ARM moves in.
