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Is there a real-world difference between 3 Gbps and 6 Gbps SAS drives in a server? I keep reading that harddrives don't even fully saturate 3 Gbps yet, so 6 Gbps is nothing gained. I'm using multiple discs across RAID 10 if that matters. Thanks!

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Some SSDs can saturate 6Gbps already – Chris S Dec 9 '10 at 19:22
up vote 1 down vote accepted

A single drive may not be able to saturate a single SAS link, but if you put many drives on single link it's very likely you will be able to saturate it.

On the other hand, most often than not you are limited by access time not bandwidth (www serving, databases, file serving in most cases). Only with video streaming or big file serving you will be limited by bandwidth, but then again, do you have 10Gbps pipe out of the server?

In short: it depends on use and storage architecture but having 6Gbps controller won't hurt.

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It depends how many disks you are using. You can Utilize the 6Gbps throughput if you are using enough disks in the RAID. 4 Disks on a RAID-10 or individual disks will not utilize that much bandwidth

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2 in a RAID 1 + 4 in a RAID 10. – AX1 Dec 9 '10 at 19:23
In that case I don't believe you will see any performance difference between the two. If you want performance look at the RPMs and get a 15k RPM drive – cpgascho Dec 9 '10 at 19:26
Also note for performance the best RAID to use is RAID 10, RAID 5 may have faster read but slower write and RAID 1 should be the same as no RAID – cpgascho Dec 9 '10 at 19:27

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