LSI LSISAS3801X 8 Port SAS Controller - 2 x SFF-8088 SAS 300 LSI00124 사용자 설명서

Low-Cost SAS/SATA PCI Express Adapters

If your solution requires direct connectivity to hard disk drives inside the server, then Host-Based (or 

Software) RAID is a viable option.  Not only do the Host-Based MegaRAID entry line adapters have 

high performance, but they are also built on the proven, OEM-tested MegaRAID stack. They ship 

with RAID 0, 1, 10, and 5 (striping with distributed parity to deliver higher performance with fewer 

disks). The MegaRAID SAS 8208ELP, with 8 internal ports and the MegaRAID SAS 8204ELP, with 4 

internal ports, are the only low-cost RAID 5 options available today; the Adaptec 2 series does not 

support RAID 5. LSI HBAs are off ered in 8 and 4-port internal connectivity options as kits and single 

packs. 

Adaptec sells a 4-port internal adapter as a kit or single pack in the 2 Series, although it does not 

have the performance bandwidth of a higher ported option.

Adaptec diff erentiates its 2 Series adapters against LSI Host Bus Adapters and the LSI MegaRAID 

entry line with a 128MB on-board cache. This expensive piece of memory may modestly improve 

performance, but it puts the data it contains at risk without a battery back-up (BBU). On-board cache 

without a BBU and without support for RAID 5 provides no tangible advantages over LSI MegaRAID 

entry line products.

Cache is most benefi cial if running RAID 1 and 10 on small block random applications (transactional, 

database, OLTP, etc); however, these are the least likely applications for these adapters. LSI SAS HBAs 

do not rely on cache because they leverage advanced Fusion-MPT™ architecture which provides 

over 140,000 I/Os per second. This superior, ultra-thin driver architecture delivers high performance 

without the extra expense of cache. In addition, LSI HBAs are built with precisely selected high-

density chips that are low-cost and power-eff ective, providing a reliable solution for your server.

As Adaptec correctly cites, Host-Based RAID 5 does place a burden on the main CPU and is a cost 

trade-off  LSI chooses to let the customer make. If your CPU does not have extra cycles available, 

then the MegaRAID entry line with Host-Based RAID is not for you. However, with today’s high 

performance CPUs, this is not a consideration for many and Host-Based RAID is perfectly acceptable. 

In fact, modern multi-core CPUs are utilized at only a fraction of power they can deliver. The LSI 

MegaRAID entry line adapters utilize 1-4% of the power in one core. 

Conversely, both Adaptec RAID and LSI HBAs with Integrated RAID are very similar in that they are 

both Hardware RAID with the computations taking place on the embedded CPU on the storage 

adapter. Adaptec RAID in the 2 Series off ers RAID 0 (striping), 1 (mirroring), and 10 (striping and 

mirroring). LSI Integrated RAID includes RAID 0, 1, and 1E (enhanced mirroring where each disk is 

logically divided by half and the mirrored data is written to the adjacent disk).

Whether requiring low-cost RAID 5, scalability, or simply mirroring for large SATA drives, LSI has the 

product breadth to service your specifi c requirements with either a LSI SAS/SATA Host Bus Adapter 

or a MegaRAID entry line storage adapter.