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PATA RAID & bottlenecking?

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April 4, 2006 8:12:33 PM

I am going to order a new Asus A8N-SLI board because I can no longer stand my freebie ECS board (bad temp sensors and the LAN has issues). I figured that while I'm at it I could set up a RAID 0. I'd like to use my current Hitachi 7k80 7200RPM 2MB PATA drive and buy a matching drive to pair with it so I don't have to buy 2 new drives. I want to use these drives because they have relatively fast seek times and have pretty good throughput as well. I would also be using a 250GB Seagate 7200.8 PATA (my current boot drive) as a backup and as raw storage and a Plextor PX-716A DVD+-RW also PATA. I'm worried about the PATA bus getting bottlenecked. I already read the RAID FAQ 1.3 and I'd put the Hitachi's as Masters on each bus...

If I had to guess the recommendation will be to use SATA which would mean that I'd need to get 2 new drives. Any recommendations on cheap drives with good seeks and decent throughput? Also, would a 16MB cache and/or SATA II help significantly? Edit: I'd rather not get Raptors because of the $/GB ratio... I'm trying to keep the price down as much as possible. I'd probably just get 2 SATA II 7k80s.

Thanks
-mcg
April 4, 2006 8:25:09 PM

There is bottlenecking every time 2 devices on the same PATA channel try to read or write because there's only 1 data 'line' for 2 devices...

Definitely keep the RAID 0 drives on different channels.

So, if your your raid is 0-mast & 1-mast and boot is 0-slave, whenever you need to read/write to both boot and raid, you'll hit a bottleneck. Also every time you read to the CD/DVD and the RAID.

If you can find a mobo with 4 PATA channels (1 for each device and a spare for the CD/DVD), you're all set. Otherwise, yep, SATA is my recommendation.

I'd get whichever drive is cheapest - there's really very little difference in performance between the 4 drive mfgs. Only one I'd avoid is Maxtor, but some people like them. My fav is a tossup between WD & Seagate.

I don't see a lot of point in 16mb cache, but many people are claiming noticeable speed increases... I'm a cynic and I haven't bought a 16mb cache one to test yet, so I'm a non-believer.

No point in getting SATA II/IO/300/2.0/2.5/whatever its called this week... Drives aren't fast enough to saturate ATA/133 let alone SATA150. (Raptor a possible exception)

Mike.
April 4, 2006 8:52:27 PM

After getting the RAID 0 I'd make it my boot drive... I guess I forgot to mention this.

I also stay away from Maxtors. All 3 that friends of mine have owned have died. Thankfully still in warranty, but not reasuring. I like both Seagate and WD, but from what I've seen the seek times on the Seagate 7200.8/7200.9 are not that great, and there really aren't any WD drives in the segment that I have benchmark data for.

I'm not (yet) a believer in 16MB caches either... thats why I asked.
I knew about bus saturation and all, I was asking more about other "features" of the next gen of SATA.

Thanks
-mcg
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April 4, 2006 9:24:27 PM

Ok, then 2 PATA channels are enough since the 250gig one will be for backup, it doesn't matter much if its sharing its bandwidth with the RAID.

Oh, what if you want to burn a DVD from the RAID? Same bottleneck :( 
Workaround could be to copy it to the 250gig before burning. :?

Samsung is good too. I agree about the 7200.8/9 Seagates - they're not that great.

Ah, I see about SATA2. NCQ is really only useful in servers or server-like situations where there are a number of outstanding disk requests. Hot swap is nice, but not useful for an internal drive. Those are the only 'big' features I recall. Hope someone else pipes up with the rest for you. :) 

Mike.
April 4, 2006 10:12:24 PM

Quote:
If I had to guess the recommendation will be to use SATA which would mean that I'd need to get 2 new drives. Any recommendations on cheap drives with good seeks and decent throughput? Also, would a 16MB cache and/or SATA II help significantly? Edit: I'd rather not get Raptors because of the $/GB ratio... I'm trying to keep the price down as much as possible. I'd probably just get 2 SATA II 7k80s.


80GB SATA HDs are in the $50 range = $0.63/GB

120GB SATA HDs are in the $70 to $75 range = $0.63/GB

250 GB SATA HDs are in the $85 to $90 range = $0.36/GB

320 GB SATA HDs are in the $115 to $125 range = $0.39/GB

(sure, you can pay more)

The 250s look to be the bargain. If you can manage to find the bucks, you'll win in the long run.
April 4, 2006 11:02:57 PM

The only reason I brought up $/GB was to say why I wouldn't go for Raptors. Since I'll have at least 160GB in the RAID (I MIGHT go for 120s), another 250GB internally, and a 120GB external, I really don't think I need the additional space of hitting the 250GB sweet spot. Plus, money is a large factor as well. I'm having enough trouble rationalizing spending $100 on hard drives let alone $200, especially since I don't forsee needing the space (I'm currently only using about 200GB of my current 330GB of internal storage).
If the money weren't so important I probably would get 2x250GB hard drives though...

Thanks
-mcg
April 5, 2006 12:28:18 AM

Quote:
(I'm currently only using about 200GB of my current 330GB of internal storage).


I hear you there. I tend to forget that not everyone uses as much disc space as me. In the last month, I picked up 120GB of music, took about a GB of photos, etc. Oink!
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