SATA drives instead of SCSI?

We currently have a raid 5 drive array on our student server for our engineering dept. It has 9 36 gig ibm sca drives.

The problem we are running into is that we got a couple of replacment drives (the old ones died) but they aren't the same exact revisions as the old ibm drives. So that in turn causes our raid array to not work properly and the old 36 scsi drives are dropping out of warranty (they were bought around 2001 or so)

My boss is wondering if at this point we should just be done with the scsi drives and go with SATA drives. They are MUCH cheaper also.

But will good SATA drives be able to handle about 400 studnets and roughly 25 professors accessing it? (NOT all at once of course, but it does get used heavily).

We just don't want the server to end up being so slow and sluggish that it makes it unbearable.

The students and teachers are supposed to keep all their created documents on their shares and work from their shares so it is constaintly being used.

What do you guys think?

Stick with scsi or go SATA?

Isn't SCSI more reliable due to smaller platter size? I'm thinking that the WD Raptors are the same way, giving up the GB's for the reliability and

I once heard a guy at my job talk about how he put generic ram in their server, it worked just fine, wut they need that there ECC for, huh (yes, he had a kentucky accent). The same thing applies here: sure, there seems to be cheaper alternatives in the regular desktop market, but you'd be sacrificing quality components, and risking downtime in the future to save a few bucks. You have to ask yourself how crucial is this system to be running perfectly for as long as possible? Is it worth it to spend a few hundred to prevent the % likelihood of failure at some point in the future?

If you do SATA RAID it's fine. The fact is that 2 SATA drives in RAID1 would give you about the same capacity as all your 9 RAID5 SCSI drives. Now it comes to HOW these drives are being used (OS, application, size of files, etc). You might be fine due to larger cache on drive, but before making such a radical change I would run some tests (use the performance monitor to find out how much these drives are being used).

This is probably to much info for this subject, but I figured what the hell.



Here's a real way to check it out and determine if it'll be for you.

Since SATA drives are slower seek times, you probably should do some testing / monitoring using performance monitoring (start, run perfmon.msc /s) -- and add counters (change performance object to physicalDisk) and run various counters. I'd recommend % disk time, Avg. Disk Queue Length and maybe a few others if you feel like it (network?). This will give you an idea of how hard your server is really getting hit throughout the day (set times from 1 hour before the full load of people to 1 hour after the full load of people). Do this for a full week and you'll have plenty of good solid data.

After you get your reports, make a judgement call. Do you want a somewhat slower drive(s) or are you taping out what you already have and need faster? Is your network your bottle neck? Plenty of questions to have answered before hand. SATAs are high capacity, slower seektime where scsi's are lower capacity and faster seektime. Transfer rates are not that much of a factor since you are hitting an instant 100Mb bottle neck when you hit the network (assuming its 100).

Reliability wise...meh, I wouldn't worry too much, if it comes with a 3 year warranty, who cares (as long as its next day service anyway)

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Originally Posted by bobo

We currently have a raid 5 drive array on our student server for our engineering dept. It has 9 36 gig ibm sca drives.

The problem we are running into is that we got a couple of replacment drives (the old ones died) but they aren't the same exact revisions as the old ibm drives. So that in turn causes our raid array to not work properly and the old 36 scsi drives are dropping out of warranty (they were bought around 2001 or so)

My boss is wondering if at this point we should just be done with the scsi drives and go with SATA drives. They are MUCH cheaper also.

But will good SATA drives be able to handle about 400 studnets and roughly 25 professors accessing it? (NOT all at once of course, but it does get used heavily).

We just don't want the server to end up being so slow and sluggish that it makes it unbearable.

The students and teachers are supposed to keep all their created documents on their shares and work from their shares so it is constaintly being used.

What do you guys think?

Stick with scsi or go SATA?

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In a production envirment I would stay with the SCSI drives. They should be 10,000 RPM drives. The Serial ATA drives are not as fast. According to Intel They dont reconmend that the use of SATA drives in a high speed raid envirment.

If its a small server and not running much info, and has very few people accessing the drive then it would a very cheap way of fixing the problem.

You should also look at the spec's on the drives. You will find out that the SCSI drives have a longer life than the SATA drives.

This is from a person that installs servers and other hardware in production machines.

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Originally Posted by garthg

In a production envirment I would stay with the SCSI drives. They should be 10,000 RPM drives.

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Why not 15,000 RPM???

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The Serial ATA drives are not as fast.

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Depends on the drive. There are still controllers "out there" that only negociate 80MB/s. SATA 150 is faster. Even more, RAID5 has slower writes than RAID1. And WD Raptor (10k RPM, 4.5ms seek, >70MB/s sustained transfer) beats many SCSI drives.

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You will find out that the SCSI drives have a longer life than the SATA drives.

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WD Raptor has 5yr warranty and 1.2mil hrs MTBF. Again, better than many SCSI drives.
Only the performance monitor can show the real stress of the array. If there is enough RAM in the server it might be just fine.

Well the more we are looking at the subject, the more we are wondering whats best?

This is strictly being used as a fileserver (not application server). All the students shares are on this server and they are supposed to use it for storing all their user created work.

I have found one SATA Raid setup that I quite like:
http://www.adaptecstore.com/index.cf...lang=US&bhcp=1

We then would fill it up probalby with 4 100-150 gig SATA drives.

Now I can understand for medium and up servers that you want to stick with scsi but would you consider our needs and uses of the server to be low end?

The average student stores about say 20-50 megs wroth of misc data on their share. There are a total of around 400 students.

So, is our use of the server considered low end/mid range/hi end/etc? Also we aren't worried too much about reliablity, since the system gets backed up regularly.

Remember, this is a school where there is no mission critical finanical type of data being stored. its mainly for student storage.

OH yeah, the server is a pentium 4 2.4 ghz, 1 gig of ram (probably going to be upgraded to 2 gigs soon) and has windows server 2003 for its os.

Bobo, what speed does your network run at? If you are using a 100 Mbit or less then I would put some thought into running the performance monitor like others have mentioned. You may be able to take the money you save by using SATA drives and use it toward gigabit equipment.

I have had no problem with WD raptors in various RAID arrays including RAID 0 in over 200 production machines. They are reliable, fast, cheap, and you can probably find them locally if you are ever in a pinch and need one replaced. I prefer to have one setup as a hot spare or at least have one that has been verified sitting in an esd bag in the server room just in case. You will also want to estimate what the demands will be on the server a few years down the road like more students, new programs that use larger data files and so on. I think I am rambling now so I am going to bed.

Just remember: all hard drives will fail, it's just a mater of when.

Our network is a peice of crap sorta 100 mbit based network. We are lucky to get 1/3 the actual throughput of a good working 100mbit network.

The network infrastructure has nothing to do with our budget so we can't move any of the money earmarked for servers to upgrading the network.

We woiuld love to have gigabit ethernet, but thats up to the trustees of the university and i doubt that is going to be happening anytime in the near future.

Quote:

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Originally Posted by bobo

Well the more we are looking at the subject, the more we are wondering whats best?

This is strictly being used as a fileserver (not application server). All the students shares are on this server and they are supposed to use it for storing all their user created work.

I have found one SATA Raid setup that I quite like:
http://www.adaptecstore.com/index.cf...lang=US&bhcp=1

We then would fill it up probalby with 4 100-150 gig SATA drives.

Now I can understand for medium and up servers that you want to stick with scsi but would you consider our needs and uses of the server to be low end?

The average student stores about say 20-50 megs wroth of misc data on their share. There are a total of around 400 students.

So, is our use of the server considered low end/mid range/hi end/etc? Also we aren't worried too much about reliablity, since the system gets backed up regularly.

Remember, this is a school where there is no mission critical finanical type of data being stored. its mainly for student storage.

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Well it looks very nice to me. It sounds like all you need is storage. That should work greate for that. I wouldnt install it in a mission critical area.

BTW the only reason I said the drivers were 10,000 RPM is because of the size and age of the drives. Yes there are new drivers running at 15,000 RPM. But at the age of the drives that he was talking about they are mostlikey not.

We choose SATA... I'm running that same card (2410SA) with SATA drives on server boxes that we've got in Dallas at Netfire, as well as our own gaming systems. (see below) These servers will accommodate several hundred people all at once in a online gaming environment. We use the WD "Raptor" drives as they are 10,000 rpm with a seek time of 5.2 ms. Fast enuf... Have never had any problems with our systems keeping up; the only thing I would warn you about is that the Adaptec 2410SA card won't always run at 66 Mhz on all mobos, particular some TYAN boards, where we've had to manually set jumpers (on the mobo) back to 33 for stability... You might consider checking with both Adaptec as well as your mobo manufacturer to ensure that no conflicts arise from combining the two.

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