Performance : SATA RAID 0 vs. SSD?


One of my clients has an old workstation currently running OpenSUSE Tumbleweed. Since the load of weekly updates is too much of a hassle, I’m planning to migrate this machine to my personal blend of Rocky Linux 8 + KDE.

Currently the workstation has two SATA disks in a software RAID 1 setup. For some operations like manipulating huge photo files with Darktable, the machine is rather slow, and my client’s not happy with it.

It turns out that recently I “migrated” my own battered HP workstation from a RAID 1 setup to RAID 0, and performance now is noticeably faster. (Like my client I have a local backup server with a RAID 1 disk array, so potential data loss is not a problem.)

I’m currently hesitating between one of the two following setups:

  1. Keep the two SATA disks and install Rocky Linux 8 using a RAID 0 array.

  2. Replace the two SATA disks with a 2 GB SSD.

I’m not a hardware guru, and before trying out something, I’d like to know: can I except the SSD disk to be significantly faster than the RAID 0 SATA array?



Assuming you are using SATA disks at 7200rpm, then even a 2.5 inch SATA SSD at around 500mb/s read/write is definitely going to be better in my opinion.

That said, I have recently replaced my laptop that was running a combination of M.2 SSD at the same speed as mentioned above, and a Samsung Evo 1TB 2.5 inch SSD. My new laptop is running 1 x M.2 SSD with 3500mb/s read/write speed, and a second M.2 2TB rated at the same speed also. Running my Windows KVM VM on this is unbelievably fast. It boots in seconds.

So I guess it all depends on what your hardware supports and if it has an ability for M.2 SSD or not. If so, the greatest speeds will be achieved with this assuming you get one with higher read/write rates since some basic M.2 can be the same speed as a 2.5 inch SSD.

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RAID 0 - don’t do it. Seriously. Don’t. I don’t care how good of a backup you have nor how fast you can restore - don’t do it. There are very limited use-cases for RAID0. But the vast majority of the time it’s just a bad idea.

As for SSD’s - almost certainly you will see a better performance going to SSD. Unless you really cheap out on some bargin-bin junk, it will perform better then spinning disks. And you say a 2GB SSD - but I suspect you mean something much larger. I’m lucky enough to live next to a microcenter where they’ve got a 512GB SSD for 25$ that will easily outperform a spinning disk. Perhaps you meant a 2TB SSD (in which case it’s closer to 150$)?

Either way, due to how fast platters can spin the most I’d expect you to get out of a spinning disk is about 150MB/s (unless you are doing something extra special with dedicated hardware raids and a bunch of disks). Those SSD’s I just mentioned are all 520+ MB/s read and write speeds.

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The M.2 is a connector format. A M.2 “slot” might offer SATA or PCIe NVMe or both.

The basic M.2 is a SSD with SATA connectivity and therefore same speed as 2.5 inch SSD that also has SATA. (Servers have more connectivity options for 2.5 inch form factor.)

The significantly faster SSD use NVMe. They – and the M.2 connectors on motherboard – differ on which version of PCIe (and how many channels, x2 or x4) the pair supports.

In addition to bandwidth the SSD have much more IOPS than spinners. One traditional HDD can do about 100 IOPS. So, two HDD of RAID-0 yield about 200 IOPS. SATA SSD can do what? Over 100 times more at minimum?

When accessing multiple small files (i.e. random access) the SSD is noticeably faster that the HDD RAID 0.

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Thanks very much everybody for your input. SSD it is then.