I am thinking of setting up a RAID 1 array of two SATA HDDs using a hardware RAID controller on a desktop
computer running Debian 11.

I would like some advice regarding a suitable controller that costs no more than about 100 pounds.

I understand that the lsi/Broadcom Megaraid RAID software can be set up for Debian :-

https://www.mybluelinux.com/debian-linu ... araid-sas/

I'm sure some may question the need for it seeing how there are software choices. Also filesystem raid exists.

Anyway, not sure you can get a real hardware raid card for that much. Maybe used from some enterprise pull could be better.

If you're okay with the used market, Dell PERC cards are a common suggestion - they're generally LSI based and many of them have appeared on the Ubuntu Server QVL, and will be recognized by megaraidcli. Do your homework on the specific card though, and seriously consider what you're attemping to do with this system - softRAID (e.g. mdadm) may be worth thinking about as well, or (imho the better way) figure out how to architect this as a non-RAID system (and for clarity: I'm guessing what I'm including in 'non-RAID' jefro would include as 'filesystem RAID').

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Thanks very much for all your replies.

I should have made the situation clearer.

I actually require to have the OS on a RAID 1 array of two SATA HDDs and the user data on another RAID 1
array of another two SATA HDDs.

I realise I can set up the user data RAID 1 using software RAID (e.g. mdadm).

The problem is with setting up the OS RAID 1. Often this is possible using the motherboard RAID.

Unfortunately, the AMD Ryzen motherboard I am using appears not to have motherboard RAID support for Linux.

So the only option for the OS RAID appears to be the use of a Hardware RAID controller. I realise such a controller
can cost hundreds of pounds, but I was hoping to find such a controller for about 100 pounds.

I am not interested in RAID arrays other than RAID 1.

You've defined a classic XY problem here - you have a solution in search of a requirement, instead of defining a root problem and looking for solutions to it. You've also duplicated threads: https://www.linuxquestions.org/quest...up-4175706965/


You were told in your other thread that both are possible in Debian.

Further, most 'motherboard RAID' is itself a form of software/fake RAID (like mdadm), just a Windows-exclusive driver in most cases. Again, see your previous thread for an answer to this using software RAID in Debian. You could also probably do this with lvm, and distros that use Anaconda may help you do this graphically.

Again, you were told this is not the case in your previous thread on the same topic.

I gave you some broad suggestions in this thread. It will require you to do some legwork to make use of that information (and part of the 'reason why' for that is that availability of used/second-hard hardware is never guranteed) - if you require to be spoonfed or need a canned solution, you may want to consider finding a system integrator or vendor who can offer a pre-built system to your specs (it's also hard to suggest you anything specific when you've provided no specifics).

Again, this is likely an XY problem, but for what its worth nobody has suggested anything else in either thread, however the exact nomenclature will vary depending on what software implementation you use. Nothing about this goal 'requires' a hardware controller (generally hardware controllers are useful if you need nested RAID, parity RAID, or a great big number of ports, but for a simple 1:1 mirror that can be done in software as well - without knowing anything about your actual root problem/requirements it is impossible to assess what would be a 'good' or 'bad' solution for your goals).

Many thanks for your replies.

My RAID questions are connected with the following situation :-

A desktop PC is being built for me by a company.

The CPU is an AMD Ryzen 5 5600x and the operating system is Debian 11.

My RAID requirement is to have the OS on a pair of HDDs in RAID 1 configuration and
the user data on another pair of HDDs in another RAID 1 configuration.

I do not know which AMD motherboard is being used.

The company told me that the AMD motherboard does not support RAID for Linux. The only
AMD motherboards which support RAID for Linux are those for very expensive Threadripper
CPUs.

The company suggested I needed a Hardware RAID controller card. They could not find any
cheap cards which support Linux, so they proposed looking for business class cards costing
in excess of 500 pounds.

Hence my quest for cheaper cards, although it may be the company would not want to use
such a card if it is second hand.

Think about following:

• RAID1 for user data is OK.
• RAID1 for user data doesn't substitute backups!
• RAID1 with two HDDs for operating system dramatically decreases system performance.
• RAID1 for operating system is useless in most cases because operating system can be reinstalled in case of hardware defect. A backup of config files is enough.
• Install operating system on a single SSD to take advantage of performance of your new Ryzen based system.
• Installing operating system to a single drive make its installation much easier.
• Software RAID for operating system is very delicate to handle because this implements a "chicken or the egg causality dilemma".

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You still have not gotten past the XY problem - you're still stating a solution (RAID1) as a requirement, and looking for ways to implement it cheap'n'dirty, which will mean buying used/spare enterprise hardware (e.g. an old Dell PERC) - there's nothing wrong with that (as in, the device probably will work fine) but performance will be sub-optimal and you're creating a lot of other potential headaches for this system (startup time will be not awesome, system performance may be not awesome, you'll give up PCIe lanes that could otherwise be used by GPU, you'll probably end up creating a legacy dependency to ensure driver support for the older card, additional cabling/mess inside the tower, the cost of four disk drives to not use half of them, etc).

What problem are you attempting to solve with RAID1? Arnulf is on the right track here - I would probably scrap this entire idea, go with an SSD for the system (depending on capacity needs and budget you could just put the whole thing on a large SSD to be completely honest), and get an external hard drive for regular backups. But again - we're guessing at your problem because you're wedded to a solution without giving us any context.

Agree on every point.

You should consider the used raid card from a pulled server.
Take a look at zfs, btrfs and lvm raids.

You can easily use raid 1 with mdadm for the OS and boot that way. It does not actually activate the raid until part way through the boot, but with raid 1 (mirrored) it does not need to for booting from one of those devices. Simply do the install on one drive that will be used for booting, then after the OS is installed use that device as one of the mirrored pair in the raid 1 array. If the current boot device fails then switch the boot in bios to the second of the pair and you will still be able to move forward.

The only thing you will need to be cautious about is that you use the raw device, such as /dev/sda and /dev/sdb for the array with the partitions defined on the array and not on the drive, and that you do not just mirror the partitions. This will ensure the boot loader will be able to look at the array and not at an individual partition.