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#21
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"Paul" wrote in message ... In article , Leythos wrote: In article , says... Nothing in that spec sheet says anything about HW RAID. The ICH5R does NOT do HW RAID. There is no uP and NO buffer. Such are requirements of HW RAID. I may be missing something here, but I don't see anything that states for something to be a raid controller that it must have a CPU or Cache. As long as the chipset, using any firmware, handles the communications with the drive and provides RAID 0/1/5 ability, it's Hardware Based RAID. If I use a non-RAID chipset and require the OS to process everything, then it's soft RAID. If I'm lucky enough to get cache and a CPU on the controller then I get even faster RAID. As I see it, the Promise or Intel RAID chipsets on some motherboards provide the functionality needed to be considered hardware RAID. Sure, they don't have their own CPU's, but they do have their own BIOS, do have their own firmware, do take commands from the OS, and do allow the creation, building, rebuilding of RAID Arrays before the OS is even installed on the system. My understanding of hardware raid is as follows: For a mirror: If the OS prepares precisely one block of memory, with data to be read or written, and the hardware solution takes that block of memory and reads or writes to two disks, and only returns "complete" status to the OS when both disks finish, Exactly. And no host based x86 code nor host I/O bus structure is involved in between. The block gets busmastered DMA-ed just once. that is hardware RAID. If the OS has to issue two commands to the hardware, saying write this to disk 0, then says write this to disk 1, that is software RAID. Exactly...that's what happens for both the ICH5R and onmobo Promise but not the 3Ware nor other true HW RAID. For a stripe: If the OS prepares precisely one block of memory, and issues one command to the hardware, and the hardware alternates writing stripe-sized chunks of data to the two drives, that is hardware RAID. Exactly. If the OS chunkifies the original large memory block, and alternates commands to the two channels to write a stripe of data to the drives, that is software RAID. Exactly and is what the ICH5R and Promise do. The difference is in the overhead. Right and for RAID 0 and RAID 1 that SW RAID overhead isn't that big. With DMA transfer, the largest overhead of data movement by the processor is removed. Right, but DMA does use bus bandwidth which can slow CPU and other I/O operations. So, these days, it will be harder to tell whether the solution is hardware or software based underneath. The first order way to tell is the presence of a uP on/in the RAID controller that hosts a full low level full robust disk driver and that's not x86 code most often. Also there'll be significant buffering onboard that RAID controller where the data is held while the RAID processes operate as you describe above. It will be hard to tell from the remaining level of overhead, to what extent the hardware hides the details of how the disk subsystem is wired up, and what it is (mirror or stripe). Exactly, the difference between SW/firmware RAID and hardware RAID for simple RAID 0 and RAID 1 is SMALL. For RAID 10 and especially RAID 5 then hardware RAID becomes distinctly superior. What you didn't describe above is RAID 5. RAID 5 can be thought of as RAID 0 plus parity. True hardware RAID 5 uses its onboard uP to calculate the parity using code hosted in the controller memory and nothing in the x86 host. That onboard uP access the data from its onboard cache thus adding NO additional host bus structure overhead. The quality of any solution will be measured in two parameter - max steady state bandwidth (HDTach) and percent CPU while doing it. So, experiment and find out. Right. Whether RAID is hardware or software is based on the level of abstraction. If the OS/driver, when viewing the hardware, thinks it is dealing with a single disk, when in fact the controller handles all the details of running the RAID, that is a hardware controller. Yes. If the OS is aware You mean any x86 host based code or driver involved in regular I/O to the array. of the details underneath, to achieve basic data transport, then it is a software based controller. Right. Notice that my definition doesn't cover implementation, so you don't need to know the private details of how it is done, to have a definition. Right but the reality of the real world provides some rather good litmus tests to differentiate hardware from software/firmware RAID. |
#23
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"Ron Reaugh" wrote in message newsGG3d.402387 If I use a non-RAID chipset and require the OS to process everything, then it's soft RAID. Nope. Correction: YES! |
#24
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Try a google search on "Ron Reaugh", peruse the results and check that the
posts on the numerous news groups are from . So Ron, you write device drivers do you? Seems to me your a beginner in the industry. - Tim "Ron Reaugh" wrote in message ... "Ron Reaugh" wrote in message newsGG3d.402387 If I use a non-RAID chipset and require the OS to process everything, then it's soft RAID. Nope. Correction: YES! |
#25
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"Leythos" wrote in message ... In article , says... So, if the idea that the OS thinks it dealing with 1 drive leads one to assume it's a real hardware raid solution, then the Promise RAID 0/1 controller on the "ASUS PC-DL Deluxe" board is a hardware raid solution. NO! The Promise has an OS level driver that knows it's talking to different disks. That means the Promise is specifically a SW/firmware RAID. The OS doesn't see it as more than a single drive. Wrong, the OS at the Promise x86 basedf driver level does see it as more than one disk and that OS level Promise driver in RAID 1 does do two writes. Re-read Paul's or my earlier posts. The two x86 based data transfer and writes is the critical issue. I would love to know where you've determined, in a Promise document, that the controller used on the PC-DL requires the OS to handle all the data to both drives instead of sending it to the controller and the controller handling the actual communications with the drives. If you can post a link to the Promise document or some source other than you own typing I would appreciate it. Re-read the whole thread. There is no place in that Promise chip nor in the ICH5R for all the things that would have to be there for it to be true HW RAID. http://www.3ware.com/products/pdf/AMCC_MPG_0519.pdf http://graphics.adaptec.com/pdfs/raid_soft_v_hard.pdf http://nas.darma.com/support/hcl.html Note the column where "not true HW RAID" is shown vs various RAID products. Both Promise and the ICH5R get "not true HW RAID". -- -- (Remove 999 to reply to me) |
#26
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"Tim" wrote in message ... Try a google search on "Ron Reaugh", peruse the results and check that the posts on the numerous news groups are from . A clear technique of a troll and stalker. When you can't carry the day technically then attack the person. You've been outclassed and are a FRAUD! |
#27
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"Tim" wrote in message ... Ron, where was the personal attack? You have been given a lot of opportunity to provide evidence for your arguments and have not produced any. You are a bald faced liar as ayone can see. |
#28
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Ron, where was the personal attack?
You have been given a lot of opportunity to provide evidence for your arguments and have not produced any. Since you claimed to be a device driver writer, my thinking was that perhaps in prior posts elsewhere you may actually have furnished evidence and information to support this. In the few I looked at (there were 10 pages of results), I saw nothing to support any of your arguments or claims. I have also researched your side of the argument and have nothing that I could add or give to your to support what you are claiming. Is that balanced? Is it fair? Me, a fraud? One thing I have learnt in life is that when a person makes a baseless accusation such as this, is that they are generally talking about themselves, either that or they are being irrational as they have some other major problem. I am not too sure why you insist on calling people names and not providing any support for your claims... You do have the google toolbar don't you? The really big irony here is that there is the remote possibility that you *could* have been right. However you have lost all opportunity at gaining credit for exposing a Major Deceipt. You can flit around news groups for the rest of your life if you wish, or you can learn to argue your case clearly and cleanly and be of great benefit to all and gain something for yourself. If you need an example of how to do that, then take a look at Paul's work. It does annoy me when I see responses come from people such as yourself that claim to be authoritative, but are wrong. Novices have a hard enough job digesting what is in front of them without deliberately misleading information. Calling people Wrong or Wacko is deliberately misleading. BTW: I suggest you check with Adaptec about your definition of RAID. Adaptec has made many RAID cards in the past that have not had cache memory as standard. Also, how do you know that the 82801 chip does not contain a processor? If it doesn't contain a processor of some sort then what is the firmware for? It seems you don't know what firmware is. If Intel wants to put a processor of some time inside such a chip and not tell anyone then thats their business. If Intel has not and has implemented their RAID purely in hardware then that is there business. Paul's definition of RAID is solid IMHO. So, again Ron, come clean. How about some evidence? Show us some evidence that supports your assertion that the OS has to issue (via the supplied driver) multiple IO's when the application thinks it is dealing with 1 physical volume? Try Windows Performance Monitor for a start and write a test app with IO's above and below the stripe size and look for a correlation between reported physical IO's and logical IO's taking into account that not all IO's are actually IO's. Since you have HDD ddk experience, then surely you can write a layered device driver to intercept the IO's from Intel driver and the physical device? I know this can be done as this is how one can implement device level encryption - PGP Disk does / used to do it. You could implement a custom Perfmon object to show counts of reads and writes etc. If you need the source code for this I can help your out. - Tim "Ron Reaugh" wrote in message ... "Tim" wrote in message ... Try a google search on "Ron Reaugh", peruse the results and check that the posts on the numerous news groups are from . A clear technique of a troll and stalker. When you can't carry the day technically then attack the person. You've been outclassed and are a FRAUD! |
#29
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"Leythos" wrote in message ... In article , says... "Leythos" wrote in message ... In article , says... So, if the idea that the OS thinks it dealing with 1 drive leads one to assume it's a real hardware raid solution, then the Promise RAID 0/1 controller on the "ASUS PC-DL Deluxe" board is a hardware raid solution. NO! The Promise has an OS level driver that knows it's talking to different disks. That means the Promise is specifically a SW/firmware RAID. The OS doesn't see it as more than a single drive. Wrong, the OS at the Promise x86 basedf driver level does see it as more than one disk and that OS level Promise driver in RAID 1 does do two writes. Re-read Paul's or my earlier posts. The two x86 based data transfer and writes is the critical issue. I would love to know where you've determined, in a Promise document, that the controller used on the PC-DL requires the OS to handle all the data to both drives instead of sending it to the controller and the controller handling the actual communications with the drives. If you can post a link to the Promise document or some source other than you own typing I would appreciate it. Re-read the whole thread. There is no place in that Promise chip nor in the ICH5R for all the things that would have to be there for it to be true HW RAID. http://www.3ware.com/products/pdf/AMCC_MPG_0519.pdf Interesting "All 3ware products incorporate an onboard processor for true hardware RAID performance." Notice, they only mention their product as factoring performance, not that it's anything more than any other RAID (except for performance). They do say this "Software RAID schemes use the system processor, occupy host memory, and consume CPU cycles." But they don't say what constitutes "software raid" - from their own documents it appears that they describe software RAID as the standard OS RAID, having nothing to do with onboard RAID controllers. The firmware and chipset interface for the Promise RAID controller on the PC-DL Deluxe clearly meets the hardware requirement as based in this document. That's flat FALSE! From your own quote above "Software RAID schemes use the system processor, occupy host memory, and consume CPU cycles." The Promise and ICH5R both do all those things..ergo SW/firmware RAID. I would also imagine that the Promise SX-6000 ATA 6 channel RAID card (which you said didn't) Nonsense. What I said was "don't know" and I went on to say that some Promise cards are semi-HW RAID. clearly is hardware RAID, even in your mind it would be, if we used your logic. Clueless. http://graphics.adaptec.com/pdfs/raid_soft_v_hard.pdf This document clearly makes NO distinction between onboard RAID controllers and other boarded RAID controllers. HUH? The issue at hand is SW vs HW RAID and NOT overboard where you've jumped. In fact, it only talks about a RAID CARD and a SCSI non-RAID card in testing. If you look at the document closely it does talk about dedicated processors and firmware, but it clearly separates software RAID as being something that is not based around a chipset, the talk about it being OS driven. The firmware and chipset interface for the Promise RAID controller on the PC-DL Deluxe clearly meets the hardware requirement as based in this document. Pure CARP as anyone who reads it can see for themselves. I would also imagine that the Promise SX-6000 ATA 6 channel RAID card (which you said didn't) clearly is hardware RAID, even in your mind it would be, if we used your logic. Clueless. http://nas.darma.com/support/hcl.html Note the column where "not true HW RAID" is shown vs various RAID products. Both Promise and the ICH5R get "not true HW RAID". So, it looks like a vendor is saying that the Promise is not "true" hardware RAID, but I don't see anything other than their linux variant that suggest where it doesn't meet the RAID spec, in fact, it only suggests that you use a different driver. I don't believe that this vendor is credible in this discussion. Wacko. |
#30
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"Leythos" wrote in message ... In article , says... Clueless. Nice response Ron, I've added you to the list of people I place no credit with (like some of the others here have done with you). Always the same pattern. When outclassed technically then attack the person...transparent. |
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