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DogEared

SCSI RAID Choices: Down to Adaptec and LSI?

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I am kinda dismayed to see LSI suck up Mylex and AMI's MegaRAID, only because it seems to leave two SCSI RAID companies. Even though LSI has a couple of product lines, it seems like only have two choices - which is better than one. ;)

I may be in the market for a new SCSI RAID controller and I was curious to see what experiences people have had with particular cards.

I'm specifically looking at dual-channel PCI-X cards (U320). The motherboard would be a Tyan K8W and the drives would be Cheetah 15k.3s. (I'm planning on building a system early next year -- Jan/Feb)

Does Adaptec measure up? I noticed negative comments about their previous generation.

I did find a thread with comments regarding LSI vs. Adaptec but I was hoping for more specific recommendations: card models and experiences.

Anything new on the horizon? (I'm not sure about SAS, but it fits my personality. :D )

Thanks for the input,

DogEared

Also feel free to throw in experiences with hotswap enclosures (internal) I was looking at the 5 and 4 drive units from SuperMicro.

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Sorry, I should have added that I currently own a 1-channel U160 model from LSI. (MegaRAID Express500)

So I have some experience of my own on a somewhat smaller scale. ;)

DogEared

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The general feeling that I get from people in the know is the Adaptec doesn't know jack about making a good RAID card.

Interpret that as you wish....

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We use both her where I work. It all depends on the application. I have a HD workstation that has 8x73GB RAID 0 on Adaptec dual channel controller and that baby flies. Adaptec doesn't offer any RAID5 SCSI320 PCI-X solution. I also have a 2010s 'zero channel" raid card in a dual AMD server and it is a under performer. Only good for making onboard scsi ports RAID"enabled".

LSI makes some good cards. As you can see, they did a M$ and bought out all of their competition. They have the high end RAID controller market nailed down. Intel offers a card based on ther 320-2 card and so do many others. Dell uses LSI for most of their high-end storage servers. Adaptec missed the boat some. They used to be the SCSI standard and have lost alot of market share to LSI&company.

I have MegaRAID 320-4x controller and it performs well and seems to be rock solid. I just happened to get a early release card back in August that had some problems. They ended up replacing the card, but it took several weeks to get a new card. I'm happy with the purchase.

BadDingo

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The general consensus is:

If RAID = "Yes" then LSI

If RAID = "No" then Adaptec or LSI

However we have exclusively Adaptec RAID cards here at work and seem fine performance wise, (All are RAID 1 config's).

There is nothing wrong with Adaptec cards per se, except that they generally lack performance when operating with RAID arrays, when compared to the LSI offerings... which is why they get a bad rap here... However they are stable and reliable, they just lack the performance of the other cards out there...

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Thanks for the replies.

I haven't used Adaptec RAID in a few years, so I was wondering how they screwed up their seemingly dominate position, especially after sucking up DPT(?) [the company that had the Century series whatever it was].

The MegaRAID 320-2X is what I have in my sights at the moment.

I was just surprised that I had a choice of "one" in the "performance class."

I'm not looking for massive capacity like BadDingo's RAID 50 setup (nice to see all of those channels with drives on 'em). I also wish I could afford one of those rack-mount drive bays. ;)

I'm just interested in high-speed workstation type stuff. And since Opterons are so much more expensive than non-MP Xeons, I need to limit the number of drives...for now. :D

Thanks again,

DogEared

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I have the MegaRAID 320-2.  LSI Logic tech support has been excellent.  They are very responsive.

I can attest to that. They created raid for me in their lab to troubleshoot my issues with harware RAID50. What is funny is that the AMI enclosures that I bought, the tech support is in the same building as the LSI megaRAID division. LSI purchased the AMI RAID products.

It's funny because they could walk to the otherside of the building a borrow an enclosure to test my setup.

LSI seems to have made the right moves in buying AMI RAID and Mylex. The have very good and solid products.

BadDingo

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I had the opportunity (for all of the wrong reasons :D ) to work closely with AMI and then LSI as the MegaRAID line changed hands. LSI definitely was a cut above support-wise. Not that AMI was bad...they were actually pretty good. LSI seemed more refined, i.e. "on the ball."

=======

I think I may buy a 320-2 rather than the -2X. Seems to be a large price jump at the momement. Maybe availability and prices will be better in February. *shrug* Or maybe I'm not looking at the right reseller.

Either way, it's not like a 66MHz bus will constrict my performance. ;)

On another note:

It's funny that I can buy two 1-channel (320-1) controllers for the price of a 2-channel(320-2). Can you create arrays across controllers?

Ex: A 2-3 disk stripe on each channel mirrored across controllers.

[ I'm having trouble suppressing my no-single-point-of-failure mentality. ]

DogEared

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I'm interested in SCSI RAID. And I did catch that review, thanks. ;)

Although I like Tom's site and have read it for many years, the following types of statements put me off occassionally:

[From the second paragraph from that article]

As incredible as this may sound, SATA has performance advantages over Ultra320 - provided it's used correctly and in conjunction with a sufficiently fast interface with the system. That is because each SATA hard drive communicates with the controller via its own fast (150 MB/s) point-to-point connection while the SCSI bus is used jointly by all devices. In certain circumstances this constellation can lead to bottlenecks in peak data traffic: A fact which is sufficiently well known for manufacturers to waste no time in fine-tuning Serial Attached SCSI (SAS). Until they're done, SATA will have its day.

[The bold within the article text is mine]

Yes, the author does go on to say "in certain circumstances" but only after implying SATA is faster than Ultra320 in general.

I just tire of reading statements like that. Both architectures are limited by the PCI bus.

Plus, ou can put four current generation drives on the U320 bus before the drive bus is a factor. Besides the fact that U320 is faster with one drive due to 15k U320 drives (faster usually means high STR)

But I'm preaching to the choir. ;)

I'm not irritated by comments like that, just annoyed. :D

DogEared

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I have three Supermicro SCA Enclosures. One is one its way back to Supermicro for reparing the backplane. It took out two U320 drives on ID0. The other two work fine. They are nice.

If you plan on running two enclosures with 10 drives, get a PC Power and Cooling 510W power supply. They are supporting my dual board and 10 U320 drives. I have the two enclosures in my main tower.

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Thanks for the recommendations.

I will only have six drives - 2x X15 18GB and then 4x 15k.3 (to be acquired)

( Right now I use two SCA adapters....ugh )

I was thinking of two of the 5-drive bays, putting drives in slots 0,2,4 (or 1,3,5 depending on numbering).

I should buy one now to dump those SCA adapters.

As for power, I currently have a 300W PSU powering my drives, and a 400W powering my motherboard (2xPIII).

I still have a SuperMicro 760 case that I haven't cut in two yet...but I plan on using two separate PSUs regardless.

I hope I'll be ready buy the rest of the system in January....

DogEared

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The MegaRAID 320-2x is using a much faster I/O processor than the 320-2 (400MHz XScale with 200MHz DDR SDRAM vs 100MHz IOP303 with 100MHz SDRAM). I would take the 320-2X if you can afford it.

I hope to receive my 320-2x next week. I'm planning to do a benchmarks comparison between the 320-2x, Elite 1600, Mylex AcceleRAID 600 and Adaptec ASR-3200s. The AcceleRAID 600 was developed by Mylex/IBM just before the LSI takeover, and never made it to market except for a few samples and evaluations units. Its based on an integrated PowerPC / Xilinx I/O processor and SCSI controller and uses DDR SDRAM. Unfortunately performance has been disappointing. The 'old' Elite 1600 performs better in desktop worloads (benched using IPEAK SPT just SR's desktop benchmarks) and is barely faster than software RAID in server workloads. Now I understand why the Mylex product line was ditched in favor of AMI's MegaRAID. The MegaRAID is simply better.

The article at THG seems to be a RAIDcore 'advertorial'. RAIDcore's technology looks nice but the test at THG is useless. Only eight drive RAID 5 configurations were tested with some pretty useless benchmarks (except for IOMeter fileserver en webserver patterns) and there is no information about the performance settings THG used on the controllers. How about RAID 0, 1 5 and 10 performance in commonly used 2 to 4 drive configurations?

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I'm interested in SCSI RAID.  And I did catch that review, thanks.  ;)

Although I like Tom's site and have read it for many years, the following types of statements put me off occassionally:

[From the second paragraph from that article]

As incredible as this may sound, SATA has performance advantages over Ultra320 - provided it's used correctly and in conjunction with a sufficiently fast interface with the system. That is because each SATA hard drive communicates with the controller via its own fast (150 MB/s) point-to-point connection while the SCSI bus is used jointly by all devices. In certain circumstances this constellation can lead to bottlenecks in peak data traffic: A fact which is sufficiently well known for manufacturers to waste no time in fine-tuning Serial Attached SCSI (SAS). Until they're done, SATA will have its day.

[The bold within the article text is mine]

Yes, the author does go on to say "in certain circumstances" but only after implying SATA is faster than Ultra320 in general.

I just tire of reading statements like that. Both architectures are limited by the PCI bus.

Plus, ou can put four current generation drives on the U320 bus before the drive bus is a factor. Besides the fact that U320 is faster with one drive due to 15k U320 drives (faster usually means high STR)

But I'm preaching to the choir. ;)

I'm not irritated by comments like that, just annoyed. :D

DogEared

I agree with DogEared, SATA is fine for desktop / small server use but put a big fat Oracle database on them and watch SCSI eat them for lunch.

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I have a 4852.

IT SUCKS

Call the company and ask them if they are aware of RANDOM induced disk failures.

Understand this: Randomly you will have one or more of your drive fail in the RAID (even though the drive is actually OK) and the company does NOT KNOW HOW TO FIX THE PROBLEM.

So you buy a RAID card and get a Russian Roulette game with your data.

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