What is HBA and why am I lost or confused by that name?:           

HOST BUS ADAPTERS:  (related see my how to pick raid card and see cross -flashing H200 and H310)
The H.B.A is not really fully defined for sure 38 years of them made, but it really only means (in this case) HARD drive adaptor or chip sets imbedded same)
Each OEM
system designer has many HBA options, some even have HBA for banks of Ethernet ports and the most common are RAID cards.
Lets do the RAID topic only here. ( I have no need for 12 Ethernet ports at home so....) No Fiber channel covered! (going obsolete now)
Assumed here is a Dell Server of any kind, but each server has a list of valid cards.
What does DELL  PERC means (PowerEdge™ RAID Controllers) see this page .

There are 2 types of persons looking for this HBA,  hardware RAID persons, and software RAID persons.(like ZFS)
I will not talk about Hardware RAID users, as that is fully covered buy each maker of card to the n'th Degree.
What most do is to flash the cards EEPROM firmware with "IT" firmware and  is now,  in true passthrough JBOD mode.
(just a bunch of disks)
The names , "IT: mode not "IR" mode flashed EEROMS (IT= HBA, IR = RAID ROM code) 
Do not use true RAID 0 mode for JBOD and software RAID or you will have nothing but pain.
The VSAN pages claim the  H730 has  working HBA mode.  (I think this is wrong)
Yes, some Dell cards are good: "SAS") prefixed cards are HBA/JBOD but have 2TB limit (HDD sizes)
Dell SAS 6/iR?  or SAS 5/iR  (the R is needed) SAS prefix  is not "H" prefixed,  LSI3081E  and 2TB limited.
Keep in mind any limits on booting. (and the 2TB limits of MBR, etc )  LSI 2008 is better chip Dell H200/H310.(flashed)
SW RAID, (software only):
RAID 0 mode is not the answer to ZFS /unRAID or other software raid . (the true controller RAID will do things to the meta data, etc, that will confuse software RAID to its doom)

Most folks wanting HBA/JBOD mode want to run software raid and will not support your RAID card or RAID 0 mode. (A LSI-9311 burned to IT mode, works and costs $20 used)
See this great UNRAID list of  cards to use and not use. (for sure the NOT recommended list !) <<<< this is all you really need to know for SW RAID.
Dell high end cards some have eHBA, that I think will not work right with any Software RAID.(it is not JBOD ready)

The Dell H200 and H310 can be crossflashed to HBA.
I think no Dell H-nnn cards are any good for software RAID, best I can tell.

Dell sells a  HBA330 mini for internal usage, too, dedicated HBA card.$80+ used, I pass on that.

And this SAS HBA ext. Adapter LSI SAS 3008 and a S130 Software raid card. Runs SATA-mark-III and PCIe3.0 both. Best for lots of disks for JBOD 10 or more.
Nothing stops you from buying generic raid card and run that.  (LSI = Avago = Broadcom) The costs for older cards is $20 realm for sure if you do the free flashing to HBA .
The problem with many users they want to have 8 or 12 or 16 more more drives (JBOD) and the motherboard does not do that.
So they buy 2 more more SATA cards for $50 each and go broke that way. (or find out they are slow)

You can buy  LSI cards from $15 or the old Supermicro card and flash them to HBA mode, zero raid, and gain 8 to 16 ports at a wack.
What you are buying is a SAS card, that does SATA like greased lighting (SAS does SATA tunneling for free)

Dells H200 (dirt cheap card) is really an LSI9211 with special Dell firmware that can be cross flashed to LSI9211 -IT mode. HBA easy, or just buy any 9211 card, used by many makers OEM  and crossflash it , a $20 cost 9211.
LSI SAS 9311-16i  (this card does 16 drives) $130
The 24port will set you back by $600 or more.
LSI SAS 9310-8i ($100) is good buy. All flashed to "IT" HBA mode. (one of the best values)  any 93nn card is a super fast card.
IBM ServeRAID M1015 ,cross flashed,  super deals on price here, we are talking $30.

The below is a big problem and I'm joking below,  a Blast From the Past.

My first HBA is below 1994, but today 24 years later I have   H700  SAS2108 based card.

Below is my HP server G7: 16 years newer than above.
That Super cap saves your bacon when power is lost (AC ) or any kind system extensive  +5vdc power loss for any reason inside the server. (like say any random CAP.'S shorting)
PHOTO HP P812: (it can not do JBOD) It is setup to RAID6 now with 8 drives in the drive CAGE. Below are the 2 riser cards and rise cage upside down. (the card cost me  $15)

HBA today just means this card (or hidding chips on the mobo)
Here  below is  LSI-SAS2008 chip from now BroadCom (Avago)
These chips can be programmed (like the 2008version too) to be a JBOD passthough device or full functional RAID controller.  The 3008 is a very fast chip.

The fact is some chips can not to JBOD (passthrough mode) or were never programmed to do so by anyone.
The LSI9211 (sold by many other names even IBM1015) does do JBOD and does have firmware to do so and is called "IT" mode (exiting "IR" mode)
This card uses LSI SAS 2008 eight-port 6Gb/s to PCIe 2.0 controller  The firmware is here, but needs to be matched to exact card. (port count and all)
The web site at Broadcom, you need to click the download box to get rid off all the other vast thing there to see firmware.
To decode the file names, is easy to hard, -4i and -8i is port count "i" means i/o ports
Thenn we have those P codes, like P17 up. P = Phase (or package),  Phase is like the prefix to Version, Phase 20 and then to the right below a subversion 7.00.
eg: \firmware\HBA_9211_8i_IT\2118it.bin           Version no:     Release date: 11-FEB-16  (the last firmware ever is here I bet) 2016 stamped.

Each zip file has both "IT & IR" binaries and the wonderful FREEDOS burner.
So my example above is the best firmware for 8port card. ( 2 SSF jacks x4 ports = 8)

RAID 0 , hacks that fail, using the wrong card or firmware for ZFS:
Wiki qoute:
If disks must be connected through a RAID or other controller, it is recommended to use a plain HBA (host adapter) or fanout card, or configure the card in JBOD mode (i.e. turn off RAID and caching functions), to allow devices to be attached but the ZFS-to-disk I/O pathway to be unchanged. A RAID card in JBOD mode may still interfere, if it has a cache or depending upon its design, and may detach drives that do not respond in time (as has been seen with many energy-efficient consumer-grade hard drives), and as such, may require Time-Limited Error Recovery (TLER)/CCTL/ERC-enabled drives to prevent drive dropouts, so not all cards are suitable even with RAID functions disabled.[40]

HISTORY OF LSI, inc. (the firmware is free to use and is at the Broadcom web site)
On 28 May 2015, Avago announced that it would buy Broadcom Corporation[23] for $37 billion, so now owns them and LSI.
I see LSI support at the Broadcom support web site.
The combined company, which would be named Broadcom Ltd.  (a very tricky fish eats fish deal)  That is why the support at at Broadcom now.

The $15 solution sold on ebay used, is this,  AOC and flashed to HBA. (lots of limits)

version 1.  3-1-2019