RAID 0 vs SCSI

[camieabz]

I was thinking of building a speedy system, but I'm not sure if RAID 0 is better, faster, more reliable, easier to build etc. etc. etc. than SCSI.

I was thinking 2 x 10.2GB Quantum AS Drives, cos I don't have money to burn.

Any opinions?

 

[Lucol]

Well, you need to get some things sorted out before you make a decision. First, RAID and SCSI are two entirely different things, RAID is setting up multiple disks in an array to gain performance or reliability, or both, depending on what level of RAID you choose, RAID 0, RAID 1 or RAID 5, these being the most commonly used. Your question might be better stated as IDE vs. SCSI, that's an entirely different subject, and it really depends on what you need. No question about it, for servers, SCSI is the clear champion, but for home use, IDE is more cost/effective. You can setup RAID on either of these, given you have the appropriate controller of course.

 

[Guest]

I think what he was asking was the performance difference between IDE disks in RAID 0 form or just a SCSI drive. Which leads to the question, ATA/100 drives? 7,200rpm? vs. what speed of SCSI? 160? More details.

 

[Guest]

what i gather from some research and reading some posts is that you will get much lower seek times using a single scsi drive but will probably get higher i/o transfer rates using ide raid over the single scsi drive. but yeah it depends on what kind of drives for each type we're talkin' about too. read some of the posts for the "speedy system drive wanted"

 

[Guest]

IBM 7200RPM 45GB drives.. in RAID 0 they do like 81MB read and 60 MB write /second..... compare that to your scsi... Im pretty sure that for those things RAID rocks... now whether you use a 10k Scsi or a 7.2k IDE... that will change more

Old addage: "Users never prosper" 😱) Long live the tweakers

 

[Guest]

yes the ide raid will beat the scsi drive in i/o transfer, (not by much though depending on the drive. 10k cheetah transfers at about 40MB/s, 15k drive > 45MB/s, soon to be released 10k cheetah at 65MB/s and the new 15k by ibm nearly 80MB/s) but most people don't need such high transfer rates unless they are doing video editing and will probably see a greater increase in responsiveness by the lower access times. something to consider though is that for the price you will get much less space for the scsi solution, but the perfomance will be better.

 

[peteb]

As said Raid 0 vs SCSI is like comparing a scooter to a rowboat - totally different things.

Raid 0 the cheap and fast way of improving disk i/o.

Your files will (depending on block size) be neatly spanned over 2 physical disks, allowing the controller to simultaneously read/write data from two disks, theoretically doubling data throughput.

In realitly they will never really do that, and to get close you need very expensive raid controllers, usually SCSI.

SCSI is a great, solid, flexible i/o connect system. Of course for all that it is expensive. MB for MB a good scis disk will probably cost you around 3 times as much as an IDE.

Good IDE systems are easy to produce - but you are limited to internal drive bays as a rule - whereas SCSI would let you build external array(s) to much larger sizes.

IDE raid is typically cheaper and lower functioned. Raid 0 is great for performance, but DOUBLES the risk of you losing data to a HDD failure. Lose either disk and your entire FS is shot and you have to restore (you do backup right?) and reinstall.

Check out these guys http://www.3ware.com/ who manufacture the first Raid5 (data is striped across multiple disks with 1 disk reserved for rebuilding data - i.e. 4 x 10GB drives gives you 30GB usable volume minus formatting overheads.)

Pete.

-Your Comany Names Could Be Here-
e-mail for application details.

 

[Guest]

Beware that putting IDE hard drives in RAID 0 will give you very poor access times. You will see a benefit in applications highly dependant on data transfer rate, but you will actually see a decline in performance on applications highly dependant on access times. RAID 0 (the type of RAID with best performance) is best used with SCSI. I would recommend one very good SCSI drive over two IDE drives in RAID 0. This would give you better reliability and better performance in most commonly used applications.