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Boot XP from CD-Rom? Need help fellas...
DrewKaree:
--- Quote from: Samstag on April 15, 2007, 12:50:19 am ---
RAID 1 is the easiest option, but how many people are willing to pay double for storage?
--- End quote ---
I'm guessing I'm missing something here, but from what you said, you need 3 drives. Shmokes said RAID 1 needs 2 drives. If people aren't going to be willing to pay double for storage, why would they then choose to shell out even more for RAID 5?
I don't much care either way (I'm following this for future use and simply for knowledge) so I don't have a stake in which musclecar means I have a bigger penis over another, so you'll have to dumb this down for one of those people who would fit the definition you're referring to - one who might not be willing to shell out double for storage.
Doesn't do very much good to seemingly talk down at the people you're trying to convince, and without further explanation that's sorely lacking from above, that's exactly what appears to be happening.
Just sayin'..... :dunno
Samstag:
--- Quote from: DrewKaree on April 15, 2007, 04:20:40 am ---
--- Quote from: Samstag on April 15, 2007, 12:50:19 am ---
RAID 1 is the easiest option, but how many people are willing to pay double for storage?
--- End quote ---
I'm guessing I'm missing something here, but from what you said, you need 3 drives. Shmokes said RAID 1 needs 2 drives. If people aren't going to be willing to pay double for storage, why would they then choose to shell out even more for RAID 5?
I don't much care either way (I'm following this for future use and simply for knowledge) so I don't have a stake in which musclecar means I have a bigger penis over another, so you'll have to dumb this down for one of those people who would fit the definition you're referring to - one who might not be willing to shell out double for storage.
Doesn't do very much good to seemingly talk down at the people you're trying to convince, and without further explanation that's sorely lacking from above, that's exactly what appears to be happening.
Just sayin'..... :dunno
--- End quote ---
Sorry about that. Shmokes understands what I was getting at but for those of you who aren't familiar with RAID levels, level 1 is a simple mirror. Put two identical drives side by side and everything you write to one is immediately duplicated on the second. As far as the user is concerned you'll only see one drive in Windows, but if you get a failure the other drive will keep you running. RAID 5 is a more complex arrangement (under the hood) that writes some of the data on one drive, some on another, and recovery data on another. For example, in a three-disk array when you write 2 gig of data you'll put 1G on drvie 1, 1G on drive 2, and 1G of useless (to you) parity data on drive 3. So while a pair of 500G drives in RAID 1 gives you 500G of protected space, three 500G drives in RAID 5 gives you double the space. Or you could get a deal on three 250G drives to get the same 500G total space at a lower cost.
So to summarize, RAID 1 requires double the cost because you need two drives for the space of one. RAID 5 requires one extra drive in addition to however many you'll use for real storage. Buy 3 drives and get the storage of one, buy 4 and get the storage of 3. The more drives you buy the lower the cost per gig rather than the fixed cost of mirroring.
Also, in RAID 5 you get a performance increase because in writing half the data to one bit of hardware and half to another, you've got twice the theoretical bandwidth. If you move a lot of data around it can make a big difference. In this respect the more drives in your array the more bandwidth you get, up to limits in your controller hardware.
I don't mean to sound like I'm talking down to anyone, and I apologize if anyone is taking it that way. I'm a RAID 5 fanboy! :P
boykster:
IMHO for workstations and personal computers, RAID1 makes MUCH more sense. You can reliably do RAID1 with pretty much any standard computer hardware (software) and hardware/software solutions are relatively inexpensive. True hardware raid cards are a bit more, but for most uses are a bit overkill.
I am a big fan of RAID5, but for larger scale storage systems, and non-volatile data. The major downside with RAID5 for workstation/pc's is slow writes. For every bit written to the array, a parity calculation needs to be done. Unless you're running a dedicated hardware raid card that has a parity calculation engine onboard, this will slow the system, and noticeably slow writing to the disk.
The other advantage of RAID1 (other than lower entry cost) is that you can put 1 drive on each channel. PATA IDE channels support 2 drives, but for a RAID application, you only want 1 drive per channel that is part of an array. This is important because the PATA spec doesn't fully isolate the 2 drives on the same channel, and it is possible, in fact likely, that if a single drive on a channel fails, that both drives will report to the OS as at least "hung", if not failed. This is due to the failed drive "taking down" the channel until a timeout occurs. On a SATA board, this is less of an issue.
Obviously, RAID5 is more "cost effective" as you scale it up as no matter how many drives are in your array, you only "lose" 1 drive's worth of storage for parity data, whereas in RAID1 you dedicate 1/2 of the physical space to redundancy. But again, most users won't have 4-8 drives in a workstation pc...you just wouldn't want to. Its loud, hot, and would require a good sized case to support that many drives....
DrewKaree:
When a drive fails in either system, how do you know it? Does it throw an error, and is it the same regardless of hardware or software setup?
Samstag:
It depends on where the RAID is handled. If it's built into your motherboard or on a PCI card you'll get an error after POST (or during). If you get a failure while the system is running then it depends on how your driver handles problems, but I'd assume they would all give you some sort of warning. If the RAID is handled in the OS you'll get an instant warning as soon as it's recognized.
You may even be able to have it fire off an email and/or automatically shut the system down if you're away fromthe computer. I have a linux server that does this.
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