IT mode is firmware that makes a SAS controller present each physical disk directly to the operating system rather than hiding them behind RAID volumes. ZFS, TrueNAS and Unraid need that, because they manage redundancy themselves and must see which physical drive returned bad data. 7 of the 11 cards we track are host bus adapters by design and need no flashing; 2 ship in RAID mode and are flashed by the community; 2 are hardware RAID cards and are not.
Prices updated
IT stands for Initiator Target, and it is the name of a firmware image rather than a feature you switch on. Load it onto a SAS controller and the card becomes a plain conduit: it initiates commands, the drive is the target, and nothing sits in between. Every physical disk appears to the operating system individually, with its serial number and its SMART data intact.
The alternative image for the same silicon is IR, Integrated RAID, which adds simple mirroring and striping and presents the result as volumes. Same card, same chip, different behaviour — which is why a used card's firmware state is a genuine question rather than a pedantic one, and why two identical-looking cards can behave completely differently in the same machine.
Distinct from both is a real hardware RAID controller — a Dell PERC H730, an HPE Smart Array. Those are a different class of product: they carry cache, often a battery or supercapacitor to protect that cache through a power loss, and they are architected around owning the array. They are good at what they do. What they do is not what ZFS wants.
ZFS is not a filesystem that sits on top of storage someone else manages. It is a combined volume manager and filesystem, and its central promise — that it detects and repairs silent corruption — depends on it owning the whole path to the disk. When ZFS reads a block it verifies a checksum. If the checksum fails, it reconstructs the block from a mirror or from parity, writes the good copy back, and records which device was at fault.
Every part of that requires knowing which physical device is involved. A RAID controller presenting one virtual disk where eight drives exist has destroyed exactly that information. ZFS can still checksum, and it will still tell you data is corrupt, but it has no second copy under its control to repair from and no way to tell you which drive to replace. It also loses per-drive SMART data, so the early warning that a disk is dying never arrives.
This is not our opinion. TrueNAS's own hardware documentation is explicit that storage should be attached through a non-RAID HBA and that hardware RAID controllers should be avoided or, where unavoidable, put into a pass-through mode — and the TrueNAS community forums have been repeating that advice for as long as the product has existed. The reason it gets repeated so insistently is the failure mode: nothing breaks visibly. The pool builds, the system runs, and the protection you believe you have is not there.
This is the part that saves money and evenings. The status column below carries a provenance label, because “this card is an HBA” and “this card has been flashed to behave like one” are different kinds of statement and should never look the same.
These are documented by their manufacturers as host bus adapters. There is no RAID firmware to replace, because presenting drives directly is what the product does. If you want to buy a card and get on with the build, buy from this group. Dell's HBA330 is worth singling out for PowerEdge owners: Dell's own technical documentation lists it under 12Gbps SAS HBAs (non-RAID), so it is the factory answer rather than a modification.
| Card | Ports | Status | From | Condition | |
|---|---|---|---|---|---|
| LSI / Broadcom SAS 9300-8i | 8 internal | IT NATIVEVENDOR FACT | $43 | Used | Buy |
| LSI / Broadcom SAS 9300-16i | 16 internal | IT NATIVEVENDOR FACT | $68 | Used | Buy |
| LSI / Broadcom SAS 9305-16i | 16 internal | IT NATIVEVENDOR FACT | $84 | New | Buy |
| Broadcom HBA 9400-16i | 16 internal | IT NATIVEVENDOR FACT | $140 | New | Buy |
| LSI SAS 9207-8i | 8 internal | IT NATIVEVENDOR FACT | $50 | New | Buy |
| Dell PERC HBA330 | 8 internal | IT NATIVEVENDOR FACT | $20 | New | Buy |
| HPE Smart HBA H240 | 8 internal | IT NATIVEVENDOR FACT | $50 | Used | Buy |
These ship from the factory presenting volumes, and reach IT behaviour through a firmware change that the community documents and the vendor does not support. They are cheap, which is the entire attraction. A listing advertising one as 'IT mode' or 'preflashed' is telling you what the seller says - verify it yourself on arrival.
| Card | Ports | Status | From | Condition | |
|---|---|---|---|---|---|
| LSI SAS 9211-8i | 8 internal | FLASHABLECOMMUNITY / SELLER CLAIM | $40 | New | Buy |
| Dell PERC H310 | 8 internal | FLASHABLECOMMUNITY / SELLER CLAIM | $33 | New | Buy |
Cache, battery-backed write paths, and an architecture built around owning the array. Good cards for hardware RAID; the wrong tool for ZFS. They are listed here because they arrive in an enormous number of used servers, so recognising them in a listing matters even if you never buy one.
| Card | Ports | Status | From | Condition | |
|---|---|---|---|---|---|
| Dell PERC H710 / H710P | 8 internal | RAID ONLYVENDOR FACT | $38 | Used | Buy |
| Dell PERC H730 / H730P | 8 internal | RAID ONLYVENDOR FACT | $49 | New | Buy |
There are three routes and the third is underrated. You can buy a card someone has already flashed, you can buy a cheap card and flash it, or you can buy a card that never needed flashing. Given how little a used HBA costs, the third option is the right default for most people and it is the one the market pushes you away from, because the flashable cards are the famous ones.
If you do want to flash a card yourself, we are not going to tell you how, and that is deliberate rather than coy. The procedure varies by card, by starting firmware revision and by motherboard; it involves booting to a specific environment and running vendor tools in a particular order; and getting it wrong can leave the card unresponsive. A summarised walkthrough written by someone who has not done it on your exact hardware is precisely how people end up with a brick.
The canonical write-ups live where they are maintained and corrected: the ServeTheHome forums and the TrueNAS community forums, where the same threads have been updated for years by people who have done it many times and have collected the failure cases. Broadcom's own host bus adapter documentation and downloads are where the firmware and the tooling come from. Read those, not us.
If you buy preflashed, treat the claim as a claim. Check the card reports as an HBA once it is in the machine — Broadcom's storage command-line tooling reads the controller and firmware back from the hardware — and do it before the return window closes rather than on the day you first need the array to save you.
Very little, which is the happy part of this page. The cards in the first group above start at around $20 on the used market, and they are a safer second-hand buy than almost anything else in a server: there is no moving part to wear out, so a pull from a decommissioned fleet is functionally a new card. The risks are authenticity and firmware state rather than wear, which is why the counterfeit checks on the HBA hub are the diligence that actually matters here.
Set against the cost of the drives going into the array, and the cost of discovering two years in that your pool never had the protection you thought it did, this is the cheapest insurance in the whole build. Get it right at purchase and it is a decision you never revisit.
The full card decoder · Which used server to put it in · Caddies and the rest of the parts layer · CMR drives for the array itself · RAID capacity planner
IT stands for Initiator Target — firmware that makes a SAS controller behave as a plain pass-through between the machine and the drives. Each physical disk appears to the operating system individually, with its SMART data intact. The alternative firmware, IR (Integrated RAID), makes the same silicon present RAID volumes instead. IT mode is not a setting you toggle in a menu; on the cards where it applies it is a different firmware image on the card.
Because ZFS manages redundancy itself and repairs corruption by reading good data from parity or a mirror. To do that it has to see individual physical devices and know which one returned bad data. A RAID controller that has merged eight disks into one virtual device has already discarded that information, and it also hides the per-drive SMART data that tells you a disk is failing. TrueNAS's own hardware documentation is explicit that a non-RAID HBA is the supported arrangement.
IT firmware presents raw disks and nothing else. IR firmware runs on the same card and adds simple RAID levels, presenting volumes rather than disks. A true hardware RAID card such as a Dell PERC H730 or an HPE Smart Array is a different class again: it has cache, often a battery or capacitor to protect that cache, and it is built around owning the array. For ZFS you want IT. IR is not a substitute, because it still interposes.
Neither, if you can avoid the question entirely — buying a card that is a host bus adapter by design means there is no firmware step at all. Broadcom's 9207, 9300, 9305 and 9400 HBAs, Dell's HBA330 and HPE's H240 are all in that category. If you specifically want a 9211-8i or an H310 because they are cheap, then a preflashed card saves you the job, but understand you are buying a seller's claim about firmware state and should verify it on arrival.
On this site's catalogue: the LSI/Broadcom 9207-8i, 9300-8i, 9300-16i, 9305-16i and 9400-16i are host bus adapters by design, as is Dell's HBA330 — Dell's own technical documentation lists it under 12Gbps SAS HBAs (non-RAID) — and HPE's Smart HBA H240. The LSI 9211-8i and Dell PERC H310 ship in IR or RAID mode and are the two cards the community flashing guides are written about. The PERC H710 and H730 are hardware RAID controllers and are not flashed to IT mode.
Some RAID controllers expose a non-RAID or JBOD mode for individual disks, and it is better than nothing. It is not the same as an HBA presenting the whole bus, the implementation varies between cards and firmware revisions, and SMART pass-through in particular is inconsistent. The ZFS and TrueNAS communities are near-unanimous that a real HBA is the right answer, and given a used HBA costs very little, the argument for fighting a RAID card is weak.
For anything that manages disks itself, yes — the same reasoning applies. Unraid wants to see physical drives and their SMART data, and Proxmox with ZFS is ZFS. If you are running Proxmox with hardware RAID underneath and a single virtual disk on top, a RAID card is coherent; you are simply choosing the card to own redundancy instead of the filesystem. What you should not do is put ZFS on top of a hardware RAID volume and believe you have the protection of either.