Hello,

I'm purchasing an adaptec u/160 raid controller for a new server. There are currently two options that I am aware of.

1st option - Adaptec 2100s single channel raid, $345
2nd option - Adaptec 3200s dual channel raid, $550

I'm only going to be using 2 drives (36 gig quantum 10k's). They are going to be in a raid 1 format (mirrored).

What are the advantages of getting the dual channel? I think it will be faster, correct? (I would have 160mb/s per drive instead of total).

Is there any redundancy advantage to purchasing the dual channel controller? And if there is, has anyone ever heard of just 1 channel going out on a raid card?

Redundancy is the thing that would persuade me to purchase the 2 channel card... The server that it's going in has a lot of redundancy... even down to dual power supplies....

All of your comments / suggestions will be greatly appreciated!

I'd say a single-channel controller is fine if you only plan to have two drives on it. There won't be any performance increase putting each drive on its own channel, because only two drives aren't going to exceed an Ultra-160 channel.

I don't think there are any particular redundancy advantages to having a two channel card.

By the way, have you looked at Mylex cards? I and others have had much, much better experiences with them than the Adaptec offerings.

I have not looked into mylex cards, but will check them out before I buy! I just figured I'd go with the "name brand" adaptec cards (although I know this does not mean they are better).

Allright, I check out mylex cards, and they look good. Has anyone had any experience setting these up with red hat 7.1? I heard a while back that 7.1 did not have very good raid support. (Something about the guy who writes the drivers is no longer developing for red hat...)

Thanks!

I haven't used RedHat on a Mylex card, but it should support it. Support for these cards has been included in all recent Linux kernels.

You might check out RedHat's site to be sure.

The driver author's site is at:

http://www.dandelion.com/Linux/DAC960.html

Mylex has a very good reputation for RAID cards, personally I think a better one than Adaptec who bought a company to aquire their actual RAID cards...

Mylex has an excellent reputation in the RAID controller business. They are not a consumer name, so many people have not heard of them before. Mylex was acquired by IBM in '98 or '99 and the two companies have worked closely together to make sure their cards perform well on x86.

Mylex used to cost a bit more than Adaptec but that may have changed.

In a bioinformatics center that we helped out with, we used an extremeRAID2000 in a RAID 5 configuration. This is hooked up to a linux cluster that is used for some serious computational simulations (they actually simulate throwing charged ions at proteins and watch how the ions find their cognate binding sites). We also used the dual channel PCI version for a persons workstation who does 3-D modeling.

Dual vs. Single
If you plan on expanding, you may want to consider the dual channel. I have found that management issues are easier when you have one card vs. two cards. Also, throughput will be greater with a dual channel. This also opens the option of running higher levels of RAID on a dual channel.

Two drives exceed a U160mb/s channel? There are plenty of drives shipping today that could exceed 160MB/s in transfers.

I know I am using them on my server. If you are doing large block copies you are more likely to achieve maximum performance on the U160 bus and thereby hit snags.

Though most people won't hit them, if you are running RAID 0 then you are essentially doubling the transactions and splitting you channel effectively in half.

Rik

Mylex is really good stuff. VA Linux systems standardized on Mylex for a reason :)
however, keep in mind that some of their older stuff (DAC960 iirc) doesn't do too well on the Red Hat 7.1 installer.

Raj Dutt