IDE vs SCSI

GordyMac · Post #1 (**permalink**) 11-16-2003, 10:41 AM

Do you use SCSI or IDE hard drives? Why?
Does the extra few RPM's from the SCSI really make a difference that you would notice?

I myself use IDE's, saves alot of money and get more space, I don't notice any difference myself.

FastNetServers · Post #2 (**permalink**) 11-25-2003, 09:22 AM

We use IDE drives on all our servers but soon we will be moving to SCSI drives just for the fact that it is more secure and reliable...This is what I have heard from a lot of people. I have to agree with you that IDE drives are must cheaper than SCSI drives

Vovex Technology · Post #3 (**permalink**) 11-25-2003, 09:36 PM

IDE is great for the less demanding server.... but if you have a lot of I/O happening on your machine it would be to your benifit to get SCSI. the extra 7,800rpm scsi has over IDE will show greatly.

If you continue to use IDE on a machine that has a lot of I/O going on you might run into "thrashing" or Channel interupts which occur when the processor losses track of where information is being placed.

Anjay · Post #4 (**permalink**) 12-28-2003, 12:09 PM

<< Do you use SCSI or IDE hard drives? Why? Does the extra few RPM's from the SCSI really make a difference that you would notice? I myself use IDE's, saves alot of money and get more space, I don't notice any difference myself. >>

Personally, I currently use IDE, however, will use SCSI in all new servers. I use IDE now, because it is cheaper, and because I never push my systems to their max. I mean, never do I have more than 100 clients per server while other times I never have more than 15.... so you can see, at times my servers have practically no one on them.
Although, in the future, when I start selling dedicated servers and for all my own servers - they'll all be with dual SCSI hard-drives. Why? Because my company pushes out as its priority: performance. You have to realise, if that SCSI drive will improve your service and performance, and your clients will be happier and it'll bring in more clients, and especially if you co-locate, then it doesn't cost too much extra. So of course, then you should go for the SCSI.

turnkey · Post #5 (**permalink**) 12-28-2003, 01:39 PM

The real diff from IDE and SCSI is the RPM's and SCSI does not bog down the CPU. The SCSI handles it's own requests with the SCSI card.

turnkey · Post #6 (**permalink**) 12-28-2003, 01:39 PM

And you can have a lot more devices (hard drives) with SCSI then you can with IDE.

imported_Andrew · Post #7 (**permalink**) 12-28-2003, 01:56 PM

The most valuable advantage with SCSI is RAID 5 capability. Theres almost no way to maintain a 99.9% + server uptime without RAID 5 (striping). Need 3 drives minimum for striping. We use 4. The data (ie your customers data) is striped across all drives. If and when 1 drive fails, the Raid card re-stripes the data across the remaining drives, with zero downtime. You can then replace the bad drive at your conveniance and the RAID card will re-strip the data - again, with zero downtime. Faster speeds are also nice. The only downfall is the higher price - but this is just an initial cost, and well worth it.

My $0.02

turnkey · Post #8 (**permalink**) 12-28-2003, 02:27 PM

Actually, RAID 1 is better for a server cause there is less strees on the system vs a RAID 5. RAID 1 does the same but without the striping.

There is also RAID 1E that does the mirror and parity but only RAID 5 does the parity and stripe.

But, in a server you would normally use 2 drives and have a RAID 1. The only real advantage of a RAID 5 is if you have external DASD then the failed drive could be hot swapped. You can't hot swap a 68 pin drive so RAID 5 internal on 68 pins would work but if it failed you would have to down the server to replace the drive.

imported_Andrew · Post #9 (**permalink**) 12-28-2003, 02:44 PM

Striping is very important. ie) if we have 2 hard drives fail, we are not down (RAID 5 across 4 drives). If you have 2 drives fail on RAID 1, you could be out of business.

Big difference.

dont think 2 drives cant fail at the same time. I personally have seen this many times. hard drives are a funny thing - you may not have one fail for years, then wammo - many go down.

Also, certain errors can be passed from drive to drive in a RAID 1 - RAID 5 is much more resiliant to this type of occurance.

turnkey · Post #10 (**permalink**) 12-28-2003, 09:51 PM

Depends on the RAID 5. For example, IBM RAID 5 can only have 1 drive go DDD and be ok, 2 dead in the water.

IBM RAID is the only raid that I know. I've been working on IBM Raid since 1997. There are probally other RAID levels out there but I think IBM is the most popular RAID out there.

imported_Andrew · Post #11 (**permalink**) 12-28-2003, 10:03 PM

Hi Turnkey,

What unit and what kind of RAID array are you running (how many drives, which controller and which machine??).

Im quite familiar with the IBM server and storage products, including RAID arrays, and depending on the machine and the array you have established, you could potentially lose upto 4 drives and still be ok (if you have a 6 drive array).

Let me know - maybe on your setup theres nothing that can be done - but maybe I will catch something youve missed - hopefully I can help....

turnkey · Post #12 (**permalink**) 12-28-2003, 10:18 PM

Andrew,

I work in the IBM test facility for the IBM ServeRAID and other products. I've been away from ServeRAID for a couple of years (went to HDD dev) but back now. Maybe the technology changed. When I get back to work this Friday I will play around with it.

GordyMac · Post #13 (**permalink**) 12-28-2003, 11:22 PM

Yeah so in other news.. this is gone way over my head ahha

imported_Andrew · Post #14 (**permalink**) 12-29-2003, 09:43 AM

Quote:

Originally posted by GordyMac
Yeah so in other news.. this is gone way over my head ahha

LOL - you started this

GordyMac · Post #15 (**permalink**) 12-29-2003, 09:54 AM

Yeah I know.. makes it that much funnier