First of all, say the conclusion: a single array of mechanical disk does not exceed 24 hard disks with the second generation of 6gb array card (lsi 9270cv series, asr 7 series or using the same chip array card is the second generation of 6gb array card. lsi 9260 series and asr6805 series are the first generation of 6gb array card, the performance is only 40% of the second generation of 6g card), 6gb solid state 8 or less select 6gb array card; Select a 12gb array card if there are more than 24 hard drives in a single mechanical disk array, or if you want to use more than 8 6gb solid states, or 12gb solid states.

  HBA card only look at the use of 12g solid state, do not use 12g solid state choose 6gb pass-through card can be.

  The following uses 2208 chip array cards such as lsi9270cv as an example. Because early 6gb and 12gb array cards are still lsi chips with better solid-state support. pmc and marvell did slightly worse. The 9270cv array card can actually achieve a throughput of approximately 4GB/S, which can basically play the speed of 24 mechanical disk arrays. The iops of the 2208 chip exceeds 40w and can basically meet the requirement of 6-8 SATA or sas solid-state I/O performance. Therefore, a single array with less than 24 mechanical disks or 6 solid-state single arrays is basically the ultimate performance of the 2208 chip array card. No matter how many disks are used, the performance will not be improved.

  The lsi 9361 of the lsi sas3108 chip provides 30 percent better performance than the 9270cv and supports a 12gb hard drive port. If you use 12gb solid state, you need a 12 GB hard drive port to maximize performance. Therefore, you are better off using a 9361 series array card. In addition, if the number of hard disks exceeds 24, the theoretical bandwidth of 8 6gb ports is too much. In this case, the bandwidth of 12 GB ports of the lsi9361 level is also required to play the performance.

  An interesting scenario is that the 6gb array card like the 9270cv connects to the lsi 12g expander card with the support of the hard drive side running at 12gb speed, that is, two or three 12g solid state, so the connection can also play the performance. But how much performance cost is for you to explore.