RAID 0 (striping) or NOT? PLEASE HELP
HI! I have the following dilemma. I wanted to buy 2 HDD of 80GB each (Hiatchi 7K250) with 2MB BUFFER and connect them in RAID 0 (striping). But a friend of mine told me I better buy 1 HDD of 160GB (Hitachi 7K250) with 8MB BUFFER? What should I do? What is the best option? PLEASE HELP me and give me some advice on t ...
This topic was started by Kale,
HI!
I have the following dilemma.
I wanted to buy 2 HDD of 80GB each (Hiatchi 7K250) with 2MB BUFFER and connect them in RAID 0 (striping).
But a friend of mine told me I better buy 1 HDD of 160GB (Hitachi 7K250) with 8MB BUFFER?
What should I do? What is the best option?
PLEASE HELP me and give me some advice on this
Thanks
PS: Sorry for my bad english
I have the following dilemma.
I wanted to buy 2 HDD of 80GB each (Hiatchi 7K250) with 2MB BUFFER and connect them in RAID 0 (striping).
But a friend of mine told me I better buy 1 HDD of 160GB (Hitachi 7K250) with 8MB BUFFER?
What should I do? What is the best option?
PLEASE HELP me and give me some advice on this
Thanks
PS: Sorry for my bad english
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your friend is half right ....
RAID is a nice thing .... but it suck due the PCI Performance limitation .... equal which Board I used ... KT333 2times and nforce2 the performance does not go over 80MB/s while both of them can run @ 56MB/s
so I switched to "something in the middle" 2 HDD but they share the work .... one is the Win + Data CD and the second the Disk for Games and so on ... so I can profit from the performance of both disks .... if one might ever stop functioning I still have one working one and most important its not that risky as RAID .... remember .... when you have datacrash one one HDD all data is lost .... if you switch motherboard and raid controller in most cases its incompatible (the array you defined) and so one .... RAID got a lot of disadvantages
RAID is a nice thing .... but it suck due the PCI Performance limitation .... equal which Board I used ... KT333 2times and nforce2 the performance does not go over 80MB/s while both of them can run @ 56MB/s
so I switched to "something in the middle" 2 HDD but they share the work .... one is the Win + Data CD and the second the Disk for Games and so on ... so I can profit from the performance of both disks .... if one might ever stop functioning I still have one working one and most important its not that risky as RAID .... remember .... when you have datacrash one one HDD all data is lost .... if you switch motherboard and raid controller in most cases its incompatible (the array you defined) and so one .... RAID got a lot of disadvantages
RAID is fast as hell, but sorta risky if either drive fails. Drives are rather reliable nowadays, and I would love the performance, but RAID will always be faster than one single drive (well, unless you're striping 2 drives from like 5 years ago, when the avg. transfer rate was all of 6 MB/s)...a RAID 0 config can even be faster than SCSI drives at 15000 RPM!
Basically,
RAID 0 is fast as hell, but sorta risky.
BTW, the PCI limit doesn't come into play here, because it's about 133 MB/s, and even with RAID 0, you'll not even break 100 (maybe bursting). Unless you have a gigabit network card on the PCI bus too, and actually utilize all the bandwidth of it, you'll be fine in that respect.
Basically,
RAID 0 is fast as hell, but sorta risky.
BTW, the PCI limit doesn't come into play here, because it's about 133 MB/s, and even with RAID 0, you'll not even break 100 (maybe bursting). Unless you have a gigabit network card on the PCI bus too, and actually utilize all the bandwidth of it, you'll be fine in that respect.
Losing 1 raid (raid-0 anyway) drive is no worse than losing 1 single drive. (both mean your data is gone for good) Raid can be troublesome with bios/driver version mismatches, but as long as you are careful it gives great speed for the price.
I'm just wondering why you are only buying a 2mb cache versions of the 80gb drives? Around here there's maybe $20 (max) difference between 2mb and 8mb cache drives, and the 8mb versions have better warrenties. I'd personally go for 2x80gb 8mb cache drives in a raid setup.
I'm just wondering why you are only buying a 2mb cache versions of the 80gb drives? Around here there's maybe $20 (max) difference between 2mb and 8mb cache drives, and the 8mb versions have better warrenties. I'd personally go for 2x80gb 8mb cache drives in a raid setup.
First of all, if you're REALLY interested in a particular technology or just want to learn more about a specific topic, do some research on the Internet FIRST. There are literally hundreds of web sites out there that discuss in great detail both the technical and philosophical aspects of RAID and submitting a query via just about any search engine will point you to most of them.
RAID 0 (zero) or striping - the word "striping" describes a method of breaking up data files into stripes or striped sets of data on 2 or more hard drives. This technique is used to split the data between those drives so that half or a quarter (if you're using 4 drives) of it goes on one drive and the other half or three quarters goes on the other drive or drives. The size of these "stripes" is determined by the sector size allocated for the striped set of drives (which is determined during setup and creation of the striped set). Generally speaking, 64KB sector sizes are about the most efficient (although it does waste some space). What that means is that the smallest file size you can create is 64KB.
In essence, when a file is created and stored on a striped set, each block of data (each file) is divided into chunks of data that are split between 2 or more drives. This speeds up (considerably) both the access times (reading) as well as the creation (writing and updating) of files. When 2 or more drives are doing the work of 1, the work-load is split between that set. Consequently, each drive operates much faster (since it's only doing half or one quarter of the work-load).
As a result, you'll get performance that will in fact equal and in some cases better the performance of a fast SCSI drive (depending on the inherent performance of the IDE drives being used). Buffer size does come into play but that is primarily a function of sequential reads (reading contiguous blocks of data off the drive). The bigger the buffer though (in general), the better the performance. And too, with IDE drives in striped mode, the performance benefits over SCSI drives is only "felt" during sequential reads and writes. Very fast SCSI drives will still be outperform IDE sets during random read/write operations where access times play a critical role in overall performance.
Now the for the bad news. Since each drive in the set stores up to half the data for any given file contained within the file system running on those drives, when 1 drive fails, guess what happens? You loose ALL the data on BOTH drives. There is ZERO (none) fault tolerance short of some "specialized" data recovery method (which I have no idea if any even exists). If you're running a striped set of 4 drives and one goes down, even though you've only lost one drive and 1/4 of the data, you've still got 4 drives that are now basically bookends (in RAID 0 mode).
In RAID 0 configuration, without backing up your data on the striped set EVERY time you add something new (a new game or whatever), you're making a very loud statement that the data on that set is NOT important to you because if one drive goes south, ALL the data is lost. Keep that bit of information first and foremost in your mind.
As long as you can restore the data that resides on the striped set, you'll be Ok. If you're only going to store games or applications that you DO have the original installation discs for and can reinstall them, then the only data you'll want to back up on a REGULAR basic (meaning at LEAST once a week) are the directories where the data that changes (saved games, created files, etc.) are contained on the set (and that's fairly trivial).
An alternative method is to configure those games and applications such that any files that are created, updated or added reside on a DIFFERENT drive (your boot partition, for example). That way if the set goes down, you can reinstall the applications and you'll still have whatever data files they created stored on another drive. It's always critical though to BACK UP any data that's important to you on a regular basis (no matter what the configuration).
So, for RAID 0 (striping) we get -
1. both SCSI and IDE/ATA drives are supported
2. minimum of 2 drives required (cheapest solution)
3. array capacity equals the size of the smallest drive x 2
4. random read performance - very good
5. random write performance - very good
6. sequential read performance - EXCELLENT
7. sequential write performance - EXCELLENT
8. cost - lowest of ALL RAID configurations
And the down-side is -
ZERO REDUNDANCY !! When one drive goes, ALL the data is lost.
Personally, my boot drive is a Seagate Cheetah 15K ultra-wide SCSI drive running off an Adaptec 29160 controller. I try and keep as little as possible (meaning JUST the operating system) on that drive and I defrag it about once a week. I have three WD 120GB 8MB buffer IDE drives, two of which are running in RAID 0 mode via a HighPoint 374 RAID controller. The third WD drive is connected to the motherboard controller. I use that third drive for backing up critical data on the striped set as well as image backups of the boot partition and I schedule those backups for the wee hours of the morning when I'm not using my system. So far, I haven't lost anything and all the drives are working well.
RAID 0 will give you the best bang-for-the-buck performance. RAID 0 using 4 (four) drives will give you AMAZING performance. RAID 0 is THE worst configuration for critical storage requirements. If you care about your data, either DON'T use RAID 0 or back up your data on a regular basis.
Later.
RAID 0 (zero) or striping - the word "striping" describes a method of breaking up data files into stripes or striped sets of data on 2 or more hard drives. This technique is used to split the data between those drives so that half or a quarter (if you're using 4 drives) of it goes on one drive and the other half or three quarters goes on the other drive or drives. The size of these "stripes" is determined by the sector size allocated for the striped set of drives (which is determined during setup and creation of the striped set). Generally speaking, 64KB sector sizes are about the most efficient (although it does waste some space). What that means is that the smallest file size you can create is 64KB.
In essence, when a file is created and stored on a striped set, each block of data (each file) is divided into chunks of data that are split between 2 or more drives. This speeds up (considerably) both the access times (reading) as well as the creation (writing and updating) of files. When 2 or more drives are doing the work of 1, the work-load is split between that set. Consequently, each drive operates much faster (since it's only doing half or one quarter of the work-load).
As a result, you'll get performance that will in fact equal and in some cases better the performance of a fast SCSI drive (depending on the inherent performance of the IDE drives being used). Buffer size does come into play but that is primarily a function of sequential reads (reading contiguous blocks of data off the drive). The bigger the buffer though (in general), the better the performance. And too, with IDE drives in striped mode, the performance benefits over SCSI drives is only "felt" during sequential reads and writes. Very fast SCSI drives will still be outperform IDE sets during random read/write operations where access times play a critical role in overall performance.
Now the for the bad news. Since each drive in the set stores up to half the data for any given file contained within the file system running on those drives, when 1 drive fails, guess what happens? You loose ALL the data on BOTH drives. There is ZERO (none) fault tolerance short of some "specialized" data recovery method (which I have no idea if any even exists). If you're running a striped set of 4 drives and one goes down, even though you've only lost one drive and 1/4 of the data, you've still got 4 drives that are now basically bookends (in RAID 0 mode).
In RAID 0 configuration, without backing up your data on the striped set EVERY time you add something new (a new game or whatever), you're making a very loud statement that the data on that set is NOT important to you because if one drive goes south, ALL the data is lost. Keep that bit of information first and foremost in your mind.
As long as you can restore the data that resides on the striped set, you'll be Ok. If you're only going to store games or applications that you DO have the original installation discs for and can reinstall them, then the only data you'll want to back up on a REGULAR basic (meaning at LEAST once a week) are the directories where the data that changes (saved games, created files, etc.) are contained on the set (and that's fairly trivial).
An alternative method is to configure those games and applications such that any files that are created, updated or added reside on a DIFFERENT drive (your boot partition, for example). That way if the set goes down, you can reinstall the applications and you'll still have whatever data files they created stored on another drive. It's always critical though to BACK UP any data that's important to you on a regular basis (no matter what the configuration).
So, for RAID 0 (striping) we get -
1. both SCSI and IDE/ATA drives are supported
2. minimum of 2 drives required (cheapest solution)
3. array capacity equals the size of the smallest drive x 2
4. random read performance - very good
5. random write performance - very good
6. sequential read performance - EXCELLENT
7. sequential write performance - EXCELLENT
8. cost - lowest of ALL RAID configurations
And the down-side is -
ZERO REDUNDANCY !! When one drive goes, ALL the data is lost.
Personally, my boot drive is a Seagate Cheetah 15K ultra-wide SCSI drive running off an Adaptec 29160 controller. I try and keep as little as possible (meaning JUST the operating system) on that drive and I defrag it about once a week. I have three WD 120GB 8MB buffer IDE drives, two of which are running in RAID 0 mode via a HighPoint 374 RAID controller. The third WD drive is connected to the motherboard controller. I use that third drive for backing up critical data on the striped set as well as image backups of the boot partition and I schedule those backups for the wee hours of the morning when I'm not using my system. So far, I haven't lost anything and all the drives are working well.
RAID 0 will give you the best bang-for-the-buck performance. RAID 0 using 4 (four) drives will give you AMAZING performance. RAID 0 is THE worst configuration for critical storage requirements. If you care about your data, either DON'T use RAID 0 or back up your data on a regular basis.
Later.
If you can afford 4 identical drives, RAID 1+0 is the best bet if you don't mind losing half the space. It stripes the drives, then mirrors those stripes so that if you lose a drive, it has a backup copy.
Pricey, but still cheaper than SCSI.
Note that RAID 0+1 has a higher probability of losing data (slim, as it requires another drive (the mirror of the failed one) to fail between the failure of the first drive and its replacement, but still)
Pricey, but still cheaper than SCSI.
Note that RAID 0+1 has a higher probability of losing data (slim, as it requires another drive (the mirror of the failed one) to fail between the failure of the first drive and its replacement, but still)
