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15k RPM IDE Hard Drives?
OutRigged asks: "SCSI hard drives have had speeds in excess of 10,000RPM for years, yet IDE has always been stuck at 7200RPM. Is there some kind of technical reason IDE drives don't go above 7200RPM? I can't imagine cost being that big of an issue, and the connection is certainly not a problem, with Parallel ATA capable, at least theoretically, of speeds over 100MB, and Serial ATA capable of even more. With hard drives now reaching sizes in excess of 300GB, don't you think we need a speed increase?" If you are wondering what the terms "Parallel ATA" and "Serial ATA" refer to, check out this article.
I've always wondered, why not simply connect all those harddrives with gigabit ethernet? Seems to be as fast, available, can be connected/disconnect while computer is on, can be used over much greater distances, etc, etc.
Some of the newer CD drives have two (or more?) 'heads', so they can read simultaneously, effectively doubling the access speed without increasing the speed of spinning. I was wondering: Can't the same be done for hard drives?
Apparently I'm not even the first one to suggest this -- for example, see here.
- Tal Cohen
I've also seen in several benchmarks, the modern 7.2k ATA drives with 8mb cache in RAID configurations with a decent (or even Promise :) controller sometimes beat out 10k SCSI in the same RAID configurations. I'm sure this is also dependent on load patterns, driver/controller efficiency, etc, but it is something to chew on.
Personally, I've mostly stuck to 5400 rpm ATA in RAID for higher reliability. For storing large files with little random access, the rotational latency isn't really a big deal, so you can make up the difference in sequential speed by adding an extra drive or two.
That said, I did recently build an ad hoc NAS computer with 180GB 7200 RPM WD ATA drives, quantity 5, in software RAID5 for about 680GB usable. I used two ATA100 two port Promise controllers (with their own additional cache), and both onboard ATA channels for the RAID disks.
The root/OS disk and CDROM was some random smallish SCSI stuff we had laying around. This was to free up available ATA ports.
That thing flys. Compared to other 3ware ATA RAID5's we have with 5400GB Maxtor disks with 2MB cache, it pushes out a lot more per/disk throughput.
I'm kinda leery considering the promise cards have cache, and also the drives have large cache, none of which is battery backed directly, but this server is not being put into a critical role, and is kept on a UPS. I've noticed that battery-backed cache seems to have lost favor in RAID controllers. There is still a danger, correct?
One thing that is striking about it is the latency. It just "feels" fast. I think that may have something to do with using Linux software raid5d rather than 3ware hardware RAID, in addition to the cache and higher rotational speed.
I've had enough abrasive sigs. Kittens are cute and fuzzy.
Do not buy the argument of "market forces" ot "high quality componenets yield high price and low demand". Half of the Slashdot crowd and most of the geeks would all buy 15K IDE drives if available, even if it would cost almost the same as SCSI. Hard disk manufactuerers already make the drives, it is just a question of slapping a IDE controller board vs. SCSI board on the drive. R&D cost is about 0.00001 canadian cent per drive. No additional investment beyond the distribution channel, and viola you have a new product, that can potentially increase your market share. There will be a low but steady demand for these drives, and if any of the manufacturers spend a little money on marketing it can actually turn into the battle of RPM (a la MHz). I do not see why this would not benefit the makers.
Well, this is my opinion, and now you have it.
Peter
Code poet, espresso fiend, starter upper.
What happened is the machine in which the array lived started to degrade (it was old) in multiple ways. The result was getting bad superblocks on several disks at once, and an array which was theoretically unrecoverable. What it taught me is that software RAID has alot more failure paths than hardware RAID. Bad memory, bad motherboard, bad controller, all can affect the integrity of your array, because the array depends on the integrity of the kernel in order to maintain a self-consistent state.
So now all my important arrays are hardware RAID controllers. Yes, if the controller goes, I could still have a bad day, but at least it is just the one component, but the whole machine, which I am depending on.
If anyone has noticed, hard drive warranties have been shrinking due to the quality, size, speed, etc of newer drives. It's getting hard to find a 3 year warranty on IDE drives lately, 1 year is becoming standard and there's even DOA warranties on some drives now. This boils down to huge sizes spinning fast...so if we wanted 10k rpm IDE drives today, that would essentially make warranties on drives nonexistent. I think the best bet us consumers can do is only purchase IDE drives with 3 year warranties, even if it will cost a couple bucks more. Manufacturers will keep pushing crappy IDE drives on us, and if we tell them we don't want short-life drives with our $$ they might decide to up their quality and evenutally we could end up with 10k rpm drives that are reliable and fast as hell. I don't know about you, but i'm sick of RMA'ing drives...