[HP Z240] PCIe available slots utilization and recommendations for RAID/HBA SAS controller

[bitsnbytes2]

Hi All,

I am scouting for a for an appropriate/supported internal SAS HBA/IT controller. I'd like to use SAS HDDs, but onboard support by the HP Z240 motherboard. I want to pool the SAS HDDs in Proxmox VE using ZFS's Software-based RAID.

As I need 4 SAS drives, I consider either a PCIex4 or a PCIex8 SAS HBA/IT controller (depending on availability and price).

Right now, I only have a graphics card on Slot#2-PCIex16. All other slots are available. My 3 questions:

1. Can I connect a "PCIe x8" SAS HBA controller card in the available Slot#4-PCIe x16[x4]? I am confused because if I take the HP installation sequence recommendations literally (see image below or link here), I am supposed to install internal PCIe storage in the Native M.2 PCIe slot or in Slot#3-PCIe x4 (which wouldn't work?!?).
2. Can I just connect a "PCIe x4" SAS HBA controller card in the available Slot#3-PCIx4, without installing anything in the Native M.2 Slot?? Again the HP installation recommendations are a bit confusing.
3. Can I connect a "PCIe x4" SAS HBA controller card in the available Native M.2 (PCIe x4) Slot? I am not sure if this is possible without some kind of an adapter.

It seems to me that I could connect the HBA controller wherever it fits, but I just wanted to double check!

Thanks a lot!

[itsmyname]

@bitsnbytes2 -- your chart seems to recommend the best order for physically inserting various components, along with specifying which slots are best for a specific card, e.g., use the X4/X16 slot for a ultra-high-speed PCIe 10 Gbit/second NIC.

[DGroves · Accepted solution]

if you don't plan on installing any other cards except for the HBA card then yes any slot is fine

however if you plan on adding a video card or any other card, then following HP's recommended card slot assignment will usually produce the best results which is what "itsmy name" also pointed out

[bitsnbytes2]

I will probably install another PCIex4 Gb Ethernet card (4 ports x 1Gb) on slot 3 (x4) and then the PCIex8 HBA SAS card at slot 4 (x16[x4]). I expect the HBA SAS card will not reach maximum performance due to it being installed in an electrically smaller slot, but I hope it will be enough for my SAS HDDs nevertheless.

I know that this setup *usually* works, so fingers crossed!

[DGroves]

the adaptec 71605 series and most LSI SAS/SATA raid cards (but not all) will work in a 4x config instead of 8x

keep in mind that if only using 4 drives on the raid card instead of 8, or if only using a 4 port card, it will still allow full speed xfers using a pci-e x4 slot as the available drives connected to the raid card will not exceed the 4 pci-e lines max data speed 

if all you want is to add more SATA ports then a LSI-92xx card with non raid firmware will be fine,.. if you need raid, skip this line

if you need JBOD/Raid,.. skip the LSI cards and use the adaptec 71605

 i personally prefer the adaptec 71605 card as it allows RAID/JBOD at the same time unlike most LSI raid cards which are raid only...........important:  the low-end LSI ROC 9240 based cards are no faster than the z840's onboard LSI raid chip due to them lacking a hardware parity processor and no ram cache/battery backup and are quite slow in any parity raid mode

highpoint also makes a HBA/Raid card in their rocket raid brand

https://www.highpoint-tech.com/USA_new/main.htm