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#21
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_R wrote:
I don't put myself in the 'SCSI-only, or server' school, but I have terabytes of storage (I would be broke if it were SCSI). Much of it is for archive purposes. Some of it is on mirrored systems--sort of non-realtime pseudo raid that's refreshed across a gigabit net. Again, you get what you pay for. Most reasonable and sensible people value their data and time when it comes to disaster prevention and recovery. As much as I hate to say it, I've probably had more trouble with Maxtor as well. I was archiving on 250g in USB 2 cases. The surprising thing is that most have been 5400rpm, which I was deliberately spec'ing to keep heat down. I like Maxtor the company, but I'm moving toward Seagate until I figure out what's up with the Maxtor failures. Using anything other than an external SCSI solution is pure nonsense! I believe Seagate's warranty is 5 years. That shows some confidence in their product. I feel lucky if I get 5 years out of a WD or Max. Using anything other than Seagate is totally and utterly foolish! As for 10 years ago, I was probably using IBM drives. Then they went downhill and I wouldn't touch them. There's still some stigma attached for me, even tho they're Hitachi now. IBM drives were never on top of the hill. WD has had firmware problems (1993 we had to reflash tons of drives that were spontaneously powering down). Their tech support initially denied problems, but later issued new BIOS. Not a confidence-booster. And I've found their tech support relatively rude, especially in regard to their own design flaws. Again, using anything other than Seagate is totally and utterly foolish when you consider the 5-year warranty and on-line RMA process. There is an interesting somewhat anecdotal project over at storagereview.com- their reliability database. I try to mention it when I can because the more ppl that contribute the better chance we have of it yielding accurate results. Storagereview.com can be a valuable site when you learn how to differentiate between fact and their biased bull****. Rita |
#22
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flux wrote:
Point is that reliability of ATA is nowhere near that of Scsi or FC. Once you get down into the desktop class drives This statement is just fiction. Drives today are roughly the same in reliability, marketing claims notwithstanding. And drive tech is finicky and rapidly changing, which means you can have a lot of 'duds' from an otherwise reputable brand. You only discover this after a year or so, as resin attcks wires, oil evaporates, bearings crash, heads overheat, or whatnot. Thomas |
#23
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In article ,
flux wrote: In article 1112979104.459192@smirk, wrote: say: desktop class drives are very cheap, have very high capacity, but they are slow, and unreliable (both in overall livetime, and also in Cheap yes, high capacity yes. Slow no, unreliable no. Buy one of each, open them up. In the ES (Enterprise) drive, you'll find small platters (about 1.5 to 2 inches), spinning at 10K (are those still available commercially?) or mostly 15K RPM. In the DT (desktop) drive, you'll find large platters, spinning at 7200 or fewer RPM. Then look at the actuator magnets. The ones in the ES drive are much larger, meaning the actuator can move much faster. Then look at how the platter cavity is sealed against outside air: ES drives are near perfectly sealed against dust. Then count the air filters: ES drive have way more. Now buy a few more drives, and put a few oscilloscopes on them, and watch what happens while they run. For example, put a scope on the servo signals (real professionals do this in software of the servo processor, amateurs have to scope the actuator drive signals), and watch how accurately the drive is servoing. Now start vibrating the drive (simulating the effect of the cooling fan in the computer, or the second drive or CD-ROM next to the drive), and watch how well the servo tracks the vibration. You'll find that the DT drive is servoing rather crudely, and can' handle vibration well (why: servo processor much less powerful). Then start doing IO while watching the servo. You'll most likely find that the DT drive will actually stop servoing while writing, with the head flying blind (why: servo processor has to do double duty running the data path, while an ES drive has separate hardware for that). Look at the PC boards of the two boards, and count the chips. Measure the Flash-ROM capacity of each drive (gives a crude indication of the complexity of the firmware of each drive, that is the software development cost that went into the drive). Get the wholesale price of all the chips (you'll have to estimate the ASICs by measuring die area). You'll find a significant difference here. Replace the scope on the actuator with a storage scope, and measure how long the actuator really needs to settle on a track after a move (you can also do this in software, but that's actually tricky business). You'll find that ES actuators move about twice as fast (and suck way more power than DT drives while doing that, there is no free lunch). Actually: drives generally use much more power when busy (writing and in particular seeking), so take a bandsaw to a few drives, and measure how thick the aluminum and copper structures that conduct heat away to the frame are; after all, you want to keep the drive cool (heat is the enemy of just about everything in the world). If you want to be neat about it, open the drive, and put a dozen thermocouples in strategic locations, button it back up, and run it for a while. Now throw a nasty workload at the drive, with a few dozen outstanding IOs at the same time (classic ATA drives can't do that at all, modern ATA drives can do it in principle, but because that capability is not used by Windows device drivers, it is implemented in a haphazard fashion). Watch the order in which the drive actually executes the IOs, and how many IOs it can queue. You'll find that under overload conditions, the ES drive acquits itself fairly well, using a pretty sane queue management algorithm. On the DT drive, it's anyones guess. Doing these tests will require a well-equipped lab, a few dozen drives, and a few weeks of time (if you are good at this kind of stuff). Or friends in the business that have done these tests, and in some cases published them (I pointed to the Dykes/Anderson/Riedel paper in a previous post). drives being sold with SATA interfaces. Unfortunately, I haved talked to experts in the field (names withheld), which have performed a teardown analysis on some (but not all!) of these ATA/SATA Let's have the names. Please ask your employer to get them through official channels. Don't forget to sign the requisite NDA agreements, and you might have to pay a little license fee here or there for information like this. Don't worry, if you use a few hundred thousand drives per year, the extra cost will not be significant. Now, naturally you can take low-reliability drives, and using Are there any such drives any more? Why are most ES drives sold with 3- and 5-year warranties, and DT drives with much shorter warranties (1 year at many manufacturers)? Coincidence? I'm not sure I believe you. Too bad. No skin off my avocado. -- The address in the header is invalid for obvious reasons. Please reconstruct the address from the information below (look for _). Ralph Becker-Szendy |
#24
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In article ,
Bill Todd wrote: Fact: ATA drives max out at 7200 rpm, while SCSI/FC drives max out at 15,000 rpm. That gives SCSI drives a 2+:1 advantage in rotational latency right off the bat. That doesn't necessary mean they are faster. In fact, they can even be slower. As for reliability, I'll let you read the paper that you previously neglected to: it's quite thorough in its assessment of the differences. Apparently not. |
#26
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In article ,
Bill Todd wrote: flux wrote: ... I'm not sure I believe you. Then you might benefit from actually looking at the material he cited rather than pulling opinions directly out of your ass. I don't believe him. Why should I believe them? |
#27
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flux wrote:
In article , Bill Todd wrote: flux wrote: ... I'm not sure I believe you. Then you might benefit from actually looking at the material he cited rather than pulling opinions directly out of your ass. I don't believe him. Why should I believe them? Because you're not a complete idiot, perhaps? On the other hand, faith-based beliefs that admit to no factual refutation are pretty popular right now, so... - bill |
#28
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flux wrote:
In article , Bill Todd wrote: Fact: ATA drives max out at 7200 rpm, while SCSI/FC drives max out at 15,000 rpm. That gives SCSI drives a 2+:1 advantage in rotational latency right off the bat. That doesn't necessary mean they are faster. In fact, they can even be slower. No, you moron: it *does* necessarily mean they are faster, for at least that particular metric. And if you check out sequential bit rates from the platters, you'll find that current SCSI/FC drives are faster there as well. As for reliability, I'll let you read the paper that you previously neglected to: it's quite thorough in its assessment of the differences. Apparently not. Certainly sufficiently thorough to put your mistaken impressions to rest. - bill |
#29
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On Sat, 09 Apr 2005 09:29:45 -0400, _R wrote:
Are there other storage groups? I only know of this one. comp.sys.ibm.pc.storage comp.mac.hardware.storage fido.ger.storage tw.bbs.comp.hardware.storage alt.comp.hardware.superdisk microsoft.public.win98.disks.general etc... The topic comes up in every hardware or computer oriented forum, whether web board, bbs, irc, usenet, etc and the dialog is usually very predictable WD has had firmware problems (1993 we had to reflash tons of drives that were spontaneously powering down). Their tech support initially denied problems, but later issued new BIOS. Not a confidence-booster. And I've found their tech support relatively rude, especially in regard to their own design flaws. Other WD firmware issues have been observed even more recently. With ATA the problem can't be flashed out. |
#30
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On Sat, 9 Apr 2005 10:00:45 -0400, "Rita Ä Berkowitz" ritaberk2O04
@aol.com wrote: _R wrote: I don't put myself in the 'SCSI-only, or server' school, but I have terabytes of storage (I would be broke if it were SCSI). Much of it is for archive purposes. Some of it is on mirrored systems--sort of non-realtime pseudo raid that's refreshed across a gigabit net. Again, you get what you pay for. Most reasonable and sensible people value their data and time when it comes to disaster prevention and recovery. For many smaller organizations or individuals there simply aren't the funds for terrabytes of scsi storage while ata may at least appear doable. Being scsi isn't the whole issue. Let's say someone bought a batch of used, old FC or SCSI Seagates' off eBay. They're not magically protected by invulnerable bulletproof drives. As much as I hate to say it, I've probably had more trouble with Maxtor as well. I was archiving on 250g in USB 2 cases. The surprising thing is that most have been 5400rpm, which I was deliberately spec'ing to keep heat down. I like Maxtor the company, but I'm moving toward Seagate until I figure out what's up with the Maxtor failures. Using anything other than an external SCSI solution is pure nonsense! not if you require compatibility with other ppl's systems. Let's say you're a consultant hired to fix other ppl's problems or configure on systems you didn't get a chance to sell them. External SCSI is the worst idea possible for portable large capacity media. I believe Seagate's warranty is 5 years. That shows some confidence in their product. I feel lucky if I get 5 years out of a WD or Max. Using anything other than Seagate is totally and utterly foolish! I love Rita-speak. Its broken-recordese. As for 10 years ago, I was probably using IBM drives. Then they went downhill and I wouldn't touch them. There's still some stigma attached for me, even tho they're Hitachi now. IBM drives were never on top of the hill. Even when they were inventing the technology WD has had firmware problems (1993 we had to reflash tons of drives that were spontaneously powering down). Their tech support initially denied problems, but later issued new BIOS. Not a confidence-booster. And I've found their tech support relatively rude, especially in regard to their own design flaws. Again, using anything other than Seagate is totally and utterly foolish when you consider the 5-year warranty and on-line RMA process. Come one. Everybody's refurbs are crap they're trying to pawn off on an unlucky slob. Testing & remanufacturing is always cursory at best. Otherwise it would be cheaper to just take one off the cookie-cutter assembly line. Seagate is no exception. That greatly diminishes the usefulness of a 5 yr warranty. There is an interesting somewhat anecdotal project over at storagereview.com- their reliability database. I try to mention it when I can because the more ppl that contribute the better chance we have of it yielding accurate results. Storagereview.com can be a valuable site when you learn how to differentiate between fact and their biased bull****. That applies to every information source. I called it "anecdotal" for a reason. Unknown credentials, unknown financial relationships, and unknown axes to grind are a part of every opinion stated as fact. But you know all about that don't you Rita? |
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