On Tue, Jun 4, 2024 at 7:56 AM Dale <rdalek1...@gmail.com> wrote: > > Rich Freeman wrote: > > On Tue, Jun 4, 2024 at 2:44 AM Dale <rdalek1...@gmail.com> wrote: > > > >> The little SATA controllers I currently use tend to only need PCIe x1. > >> That is slower but at least it works. > > The LSI cards will work just as well in a 1x. That is, assuming you > > only plug as many drives into it as you do one of those SATA HBAs and > > don't expect miraculous bandwidth out of them. > > So the LSI controllers are a option, just a little slower. Cool.
No, they're just as fast if not faster than the SATA controllers. The LSI HBA in a 1x slot will be slower than the LSI HBA in a 4x slot, which will be slower than an LSI HBA in an 8x slot. That is, assuming you're bandwidth-limited. The SATA controller you're used to can't put any more data through a 1x slot than an LSI HBA. The reason the HBA has an 8x slot is so that it can move larger amounts of data. The SATA board is marketed to consumers who care more about cramming more drives into their system than whether those drives operate at full performance. They also tend to have fewer ports- if you only are adding 2 SATA ports, then a 1x slot isn't a huge bottleneck. The bottom line is that if you are using an older v2 HBA, then it can transfer 500MB/s per PCIe lane. If you're only transferring 100MB/s then it doesn't matter how many lanes you have. If you're transferring 4GB/s then the number of lanes becomes critical if you need to sustain that bandwidth. If you're using the HBA to cram 4 5400 RPM HDDs into your system that is a very different demand compared to adding 16 Micron enterprise SSDs. > The > main reason I wanted to go with the SAS to SATA controller, number of > drives I can connect. Keep in mind, I need to get to almost 20 drives > but with only one card. Yup, getting 8/16 SATA disks on one HBA isn't a problem. Depending on how fast those drives are and your data access patterns, the number of PCIe lanes might or might not be an issue. Just add up your total data transfer rate and look up the PCIe specs. -- Rich
