nVidia FakeRAID
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@PSX_Defector said:
Any and all cards using SAS can pierce the veil of disk abstraction to the disk level.
How are you accomplishing that? Using either SAS or SATA (two different things) hardware RAID, how are you attempting to pierce the veil? The drives are not even exposed. Rarely is there even a manual option to do so. How are you doing this exactly?
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Also, by stating that, by extension you are saying that SAN, since a SAN over iSCSI is just a SAS array, cannot encapsulate its drives either.
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There is a reason why people complain about the inability to get SMART data off of drives on Adaptec controllers. Even if you wanted to access it, there is rarely an option to disable the encapsulation and turn the RAID aspects of the card off. This is why the drives get presented as individual RAID 0 arrays instead of raw drives. The encapsulation is so complete that you can't even work around it effectively, even working at the card level.
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scott, you have a tendency of saying its a particular vendor/ company that is responsible for things like this. I really think you should amend your title to include all other vendors that do this and not just pick out 1. It is equal to saying target got hacked, but then leave out home depot, jimmy johns and everyone else that was hacked as well.
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@scottalanmiller said:
Like I keep explaining over and over, FakeRAID is really RAID. It just isn't hardware RAID. Chipset RAID is hardware RAID and not part of the discussion.
But everything you are talking about IS chipset RAID.
It's implemented in the firmware, abstracted by protocol, and uses cycles from the CPU on the board to perform calculations. It's hardware in the fact that it's controlled at the lowest level with regards to the hardware. It's software in that it is controlled within Windows through applications.
This is the same discussion everyone was having back when Intel first released it on their ICH6R southbridge.
It only seems as though Linux zealots are calling it fake.
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@david.wiese said:
scott, you have a tendency of saying its a particular vendor/ company that is responsible for things like this. I really think you should amend your title to include all other vendors that do this and not just pick out 1. It is equal to saying target got hacked, but then leave out home depot, jimmy johns and everyone else that was hacked as well.
I said nothing of the sort. My post was a question, so that I could answer another question, wondering if nVidia, known for making FakeRAID, also made chipset RAID. No one has attempted to answer my question at all, but it is a question specifically about what nVidia does.
I think people often read into what I write. I'm just asking a question here, not attacking a vendor. I should be able to ask support questions too.
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@PSX_Defector said:
But everything you are talking about IS chipset RAID.
Absolutely not. I'm specifically asking if nVidia make chipset RAID. I know that they make FakeRAID, no question there. The question is, do they make chipset (hardware) RAID and, if so, how do you identify it.
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@PSX_Defector said:
It's implemented in the firmware, abstracted by protocol, and uses cycles from the CPU on the board to perform calculations. It's hardware in the fact that it's controlled at the lowest level with regards to the hardware. It's software in that it is controlled within Windows through applications.
There is chipset RAID that does not use the CPU and is hardware RAID. It encapsulates. This is fact. The nVidia stuff that I have seen first hand uses the CPU (no hardware RAID) and does not abstract anything (no encapsulation.)
FakeRAID has the nasty tendency to get broken because of a missing driver and software accessing the drives directly because there was no hardware RAID encapsulating it but the system admin doesn't realize that there is software RAID so doesn't account for it.
Hardware chipset RAID like AMD's offerings doesn't have that limitation. The RAID itself is in hardware. No faking anyone out about it.
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@scottalanmiller said:
I think people often read into what I write. I'm just asking a question here, not attacking a vendor. I should be able to ask support questions too.
I'll take some blame for derailing this, but unless someone out there has made a list of them, or if there is some other way to tell, I really dont see how we can answer your original question.
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@PSX_Defector said:
It only seems as though Linux zealots are calling it fake.
Or only Intel zealots calling it hardware. If it doesn't exist in hardware, it's fake.
And Windows people call it fake all of the time. If it exists only with software, it isn't hardware. Easy peasy.
FakeRAID is almost always targeted to fake out Windows Admins. Linux Admins are often ignored by the driver makers and so Linux Admins rarely have the vendors bothering to try to fool them into thinking that it is hardware. You are confusing the idea of a zealot with someone knowledgeable. Two very different concepts. If you install Windows onto a FakeRAID system and don't know that it is FakeRAID you will accidentally destroy your array without knowing it.
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@scottalanmiller said:
@PSX_Defector said:
SAS is just SCSI commands over SATA.
Huh? There is no ATA protocol in SAS. SAS is pure SCSI.
SAS is an encapsulation of SCSI protocols over a SATA interface. Nothing I said is saying it uses ATA, although it can speak at that level.
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@MattSpeller said:
I'll take some blame for derailing this, but unless someone out there has made a list of them, or if there is some other way to tell, I really dont see how we can answer your original question.
Well, my understanding is that nVidia never made any. So the list is just "none". Someone in another forum thought that having a RAID driver meant that they couldn't have FakeRAID so I was trying to determine if we had to look into the chipset to find out if that was true in this case or if by the nature of it being an nVidia chipset if that ruled out hardware RAID as an option.
I'm pretty sure that it does.
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@PSX_Defector said:
SAS is an encapsulation of SCSI protocols over a SATA interface. Nothing I said is saying it uses ATA, although it can speak at that level.
SAS is SCSI over Serial. SATA is ATA over Serial. If you put anything over SATA it is using ATA. You can't use the Serial ATA interface without using ATA. So yes, it's what you said.
SAS is just SCSI, there is no ATA (and therefore no ATA) involved. iSCSI is also serial and by extension, a form of SAS.
I think maybe you are confusing the serial cable with being a SATA interface? SAS and SATA are unique protocols. They happen to share some cabling options, nothing more. SAS doesn't ride on SATA nor does SATA ride on SAS. SAS is the more efficient of the two.
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So, using SCSI or ATA commands, whatever is handy... how are you piercing the veil of hardware array encapsulation? Either it is a SmartArray P400 or a EMC VNX or an HUS whatever... how are you getting to the underlying devices past the array encapsulation?
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@scottalanmiller said:
There is chipset RAID that does not use the CPU and is hardware RAID. It encapsulates. This is fact. The nVidia stuff that I have seen first hand uses the CPU (no hardware RAID) and does not abstract anything (no encapsulation.)
Unless it has a dedicated CPU, where do you think those cycles are coming from?
nVidia doesn't make dedicated RAID chips.
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Further derailment (ignore at will)
At what point do you get a reasonable controller for home / soho use? (initially 4 drives, expanding to 8 soon)
http://www.newegg.com/Product/ProductList.aspx?Submit=ENE&IsNodeId=1&N=100007607 50001833 50001329
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@PSX_Defector said:
Unless it has a dedicated CPU, where do you think those cycles are coming from?
nVidia doesn't make dedicated RAID chips.
No Harware RAID maker does. They buy them from other vendors. Super high end devices like NetApp use custom ASICs so you could argue that they are chip makers. But normal hardware RAID uses ARM, Power or possibly Sparc chips. Nvidia, to do hardware RAID like AMD, would put the RAID processing into the RAID chipset.
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@scottalanmiller said:
So, using SCSI or ATA commands, whatever is handy... how are you piercing the veil of hardware array encapsulation? Either it is a SmartArray P400 or a EMC VNX or an HUS whatever... how are you getting to the underlying devices past the array encapsulation?
You query it through whatever protocol you are using.
http://www.tinkertry.com/msminstallonwindows/
In dedicated hardware RAID, you talk to the card, the card tells you what you need to know. In chipset based RAID, it talks to the southbridge (Intel) or HT chip (AMD). Software RAID presents to the OS individual drives, it's ganged up logically to the OS specs.
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@MattSpeller said:
Further derailment (ignore at will)
At what point do you get a reasonable controller for home / soho use? (initially 4 drives, expanding to 8 soon)
http://www.newegg.com/Product/ProductList.aspx?Submit=ENE&IsNodeId=1&N=100007607 50001833 50001329
Easy answer... when it makes sense
It's not cut and dry. Software RAID is completely viable except for on VMware where it is impossible, for a home lab. Even on Windows. In production Windows / HyperV software RAID is not really very viable, but other than that, OS and FS level software RAID is often the more enterprise choice. It really comes down to what the purpose of the lab is (if it is to learn hardware RAID, you need hardware.) But if the RAID is only to combine drives into an array, you don't need hardware for that.Size of the array is not a factor unless you have controller limitations (AMD hardware limits to just two drives, for example.)
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@PSX_Defector said:
In dedicated hardware RAID, you talk to the card, the card tells you what you need to know.
It tells you what it wants to tell you. The array is 100% encapsulated and the array tells you want it wants you to believe. It exposes at will and never by accident. You can't read or write to individual drives, only the array.
With FakeRAID not only can you, but often you will by accident. If the driver crashes, for example, you would suddenly have access to two (or more) raw drives with the system having no idea that there was supposed to be RAID there. With hardware RAID, that can't happen.
