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I'm using a ThunderBay 4 external enclosure as my main storage and backup unit. Recently I bought two 1TB Samsung EVO 860 SSD to improve performance of my data drives. I installed them using NewerTech adaptors and formatted them in RAID 0 using Disk Utility RAID assistant. (I already tried with OWC RAID software with same results)
So I have:
- The two first bays with the SSDs in RAID 0 (for data)
- The following two with 2TB HD in RAID 0 (for backups)
The problem is that I'm getting write speeds of around 100MB/s on the data RAID when I should be getting around 800MB/s.
Read speeds are as expected, around 750MB/s.
Without RAID, the same happens, I get around 500MB/s read speed but only 100MB/s write speeds.
Any idea of what could be causing this?
UPDATE: After trying with all available chunk sizes (from 32k to 256k) for the RAID, still getting the same results.
Extra inforamtion
- Using 15" MacBookPro13,3 (2016)
- MacOS Mojave 10.14.1
- Measured with both BlackMagic Disk speed test and iStatus menus.
- Drives firmware revision: RVT01B6Q
Pablo Lorenzo
Posted 2018-12-06T10:35:13.207
Reputation: 33
1Firstly check the firmware. Also manually run trim on them. – davidbaumann – 2018-12-06T10:47:53.020
I updated the post to reflect the firmware version, I doesn't look that there is an update on Samsung website. Now I'm trying to find how to run trim in an external drive – Pablo Lorenzo – 2018-12-06T11:23:37.687
Actually I only know how to update the firmware using Samsung Magician... – davidbaumann – 2018-12-06T12:41:15.210
@PabloLorenzo - Depending on the controller, it might not support TRIM, have you contacted the manufacturer for assistance? – Ramhound – 2018-12-06T19:09:08.847
I did, still waiting for an answer. I don't think is a trim problem anyway – Pablo Lorenzo – 2018-12-06T19:45:46.337
Is your BIOS/UEFI set to ACHI? Is write caching enabled? It might also be some incompatibility with the SATA(?) ports. I also note this advertisement found on the ThunderBay 4 site: "I’m getting about 400—500MB/s", so it seems to me that it's doubtful you will get 800MB/s with it. – harrymc – 2018-12-08T12:31:20.407
Remove the NewerTech adapter to remove a variable from this equation. – HackSlash – 2018-12-10T16:56:31.560
1Do both RAID volumes behave the same? I assume without the new SSDs you got the high writing speed? I assume the HDs/SSDs in use are SATA? Can you attach them directly to a e/SATA controller an measure the MB/s (without the raid or any other interface in between)? – Albin – 2018-12-12T15:03:03.403