What to look for in a SAS Controller.

[Beholder2]

Hey I'm new to SAS and RAID, in fact I have no clue what RAID levels are or anything. Basically I'm going to have several SAS 10k 15k drives in a new system i'm putting together and don't know what to look for in a controller card. Not really concerned about compatibility with SATA/II but want something that can handle i/o from multiple drives as this system will act a workstation and a server. Any guidance would be great.
Cost isn't really an issue right now and I won't need support for more than 8 internal drives.
Rob

 

[kjv1611]

If price is no issue, and you're unsure about it, what about purchasing a prebuilt/preconfigured (retail) SAS setup?

 

[kjv1611]

As a matter of fact, they've reviewed several different setups and options for this sort of thing over at www.tomshardware.com . Try going there, and looking around or searching.

 

[attrofy]

If you haven't come up with a solution yet, here are some good links that will just about exhaustively cover RAID setups.

http://www.pcguide.com/ref/hdd/perf/raid/conf/index.htm

http://www.storagereview.com/guide2000/ref/hdd/perf/raid/levels/index.html

Both of these appear a bit simplistic, but once you getting diggin, you find these are both very "deep" leveled web sites.

And of course, there is always Wikipedia:

http://en.wikipedia.org/wiki/Redundant_array_of_independent_disks

Although these won't tell you which system setup is best, it does give you a good foundation of what you want to do.

My personal reccomendation, since cost is of no concern, go with SCSI and skip the SATA stuff. I have had good luck with Highpoint controllers for both SCSI and SATA RAID's. Depending on what your application will be with this setup, RAID 5 has proven itself over time, and unless you are specifically doing some specialized application (like video editing or something else) this will offer the best performance bang for the buck with redundancy capabilities.

One last bit of personal reccomendation - overbuy the size and performance of what you think you will need. As with most circumstances, once a system is in place, people find a reason to change the nature of its scope, and things get "small" quickly. Also, if you go SCSI, go for the 15K drives. Lastly, buy AT LEAST one extra HDD. It seems no matter how mainstream the drives are when you buy them, 6 months later you can't find the exact duplicate drive to rebuild a crashed array. My personal preference is to buy a few extra drives and stoer them on a shelf so that the array can continual be rebuilt while awaiting RMA's, special orders, etc.

 

[attrofy]

One correction, after thinking about it, LSI was the brand I have used for SCSI controllers. I am not sure Highpoint makes a SCSI controller, and if they do, I am sure that I haven't used it. Our current server is using the Highpoint RocketRAID 1820A for 5 SATA drives. I became quite "intimate" with this card after a server overheat, and got to know the inner workings of the factory and tech support software available. It is a solid product and their tech support is decent. I still reccomend the SCSI if cost is of no concern.

 

[Beholder2]

Thanks for the recommendations I've researched raid a bit since I posted this. I'll definetly check out the boards you mentioned. I'm going to go with the new seagate drives 15k 146g SAS 8mb cache x2.. From what i've read raid 0 will fulfill my needs as I really need fast transfer rates rather than redundancy. I'm just a little concerned if one drive becomes corrupt and my data is lost, how often would this occur? I've always bought seagate in the past I just hope their sas drives are as reliable.

Sorry for the delayed response

 

[kjv1611]

If you are concerned about a drive becomming corrupt or losing data, why not have a backup process scheduled to run to another RAID array, say in RAID 1, 5, or 10 in order to backup whatever is important.

If you need a backup of the system software, then maybe you could create an extra image of the OS and program files, and back that up on the "backup" array.

Just a thought.

 

[attrofy]

You might also consider 0+1 as an option. But truthfully, if you are considering a redundancy option, Raid 5 is the most trouble free. Even the inconvenience factor of having to rebuild, then restore a 0+1 arrary is more trouble then it is usually worth. The minor performance gain from RAID 0 is negligible compared to the ability for the RAID to rebuild itself in a crash. I have run two servers side by side with Rid 5 and Raid 0+1, and in real world configuration - ACTING AS A SERVER - there was no noticable difference between the two RAIDS. RAID 0 *in most situations* usually offers noticably increased performance in a workstation environment only. But as you said this is an option, then be forewarned that the risk factor of a complete data loss increases with every HDD you add to the array. Compiling or other forms of digitization (modeling, videos etc) will show the most noticable results where the drives have to churn out huge amounts of read-writes. For any sort of data storage, I would strongly reccomend something with redundancy. If you need data storage as well, you should consider a dual option as kjv1611 has mentioned.