Thanks for your feedback and the explanation
The mentioned Intel controllers are RAID controllers, as you described they are not what I am looking for. I need a "simple" HBA.
I already read a lot about the LSI 2008 chipset. There are a lot of OEMs out there ~> link | Here is also a list of the other OEMs ~> link
But I am worried that the chipset is too "old". I want to stay with the card for at least 5 years, therefore I was looking for cards with the newer LSI 3008 chipset.
For the moment the LSI 9300-8i (link) is on top of my wishlist. It can handle 8 disks and has the new chipset generation.
By the way the HP220 (link) card is a good alternative to the M1015. It has a LSI 2308 chipset (according to the above link) and you can get it for ~150€.
I am currently at 15TB with 5 WD Reds (3TB version).
The cost per TB is almost the same: A 3 TB WD Red costs ~110€ (37€/TB) a 4 TB WD Red costs 160€ (40€/TB).
I would get ~90€ per drive if I would sell them. This gap is too big for me and I am pretty sure in six months I am facing the controller problem again
But perhaps I am too anxious, due you have "speed problems" with your LSI 2008 cards?
Yes, the cards I've linked are RAID cards. However, they also support passing through the drives, as well.
The M1015 has two firmware options for it: IR (RAID) and IT (HBA). However, I've found that the IR firmware actually works better. .... and lists the drives in a rational order (mostly).
As for the LSI 2008 chipset, it supports 6Gbps speeds, That means SATA III. But to make a point here, the drives are never going to hit that speed, which would be 768MB/s. An SSD may. But your spinning hard drives are definitely not.
Couple that with the PCI Express 2.0 8x interface, you would need to run 35 drives at 120MB/s to start bottlenecking the connection.
So, I recommend these cards because they may be a bit older, but they're absolutely, completely relevant still.
And if you're interested in one of the cards, I could see about flashing it to IT (HBA) mode. But as I said, it's not necessary as the IR mode works as both RAID and HBA.
I built a new server and am now using a HighPoint RocketRaid 2760A, only because it can take 24 drives; otherwise I would still be using the LSI 2008. The speeds on the HighPoint card are much the same as they were on the LSI 2008.
Since ... well you were agreeing with most of what I was saying, I've edited the quote.
As for the card... an SAS Expander would have solved the issue as well. I've linked an Intel one. It gets 20 additional drives, by expanding the one SAS connection to 5 additional ones. And you could connect two of these expanders and get a total of 40 drives. If that's too many, they make internal to external adapters for these SAS connections.
Doing a scrub, which means checking all data and checksums in the array, I still get 600+MB/sec accross (the array is fully encrypted btw, employing a mix of seagate and hitachi 3TB/7.2k disks).
The PCIe 2.0x8 cards might impose an electrical problem, but only if the next gen PCIe type slots are not downward compatible....but there are PCIe3.0 versions out there.
A PCI Express 2.0 8x (8 lane) card has a max throughput of 4GB/s (that's gigaBYTE, not gigaBIT). So seeing 600MB/s or higher is still not even close to saturating the bus, in theory.
As for backwards compatibility, that's ... more or less mandatory for the specification, IIRC. However, the Intel Expander cards have a Molex power option, so ... it shouldn't really matter.
And Wiki indicates that PCI Express 4.0 is maintaining backwards compatibility, so should be a moot point.