Raid 0 - Slow Read Speeds

[taiyra]

Hi,

so, I'm currently having a really strange issue. I've been running 3 SanDisk SDSSDH3 1TB SSDs in RAID 0 (Raid 0 is fine for what I use them for and they were cheaper than 3TB of Nvme) for about 2.5 years now.

A few days ago, I noticed, while copying files, that the read speeds are really low. Write is fine. After checking with CrystalDisk, they were at 250MB/s read while 1.3GB/s write.

The drives themselfs seem fine, I verified the array with Intel RST. Since I've never seen an problem like this, I'm not sure how to find a solution.

 

SMART looks fine for all of them (attaches picture), but when benchmarking the behaviour is really strange. And in normal use, the array just feels slow.

 

I'll appriciate any ideas on how to solve this problem.

Thanks.

 

 

If relevant, the other PC components:

i7-8700k

ASUS ROG Strix Z370-F

32GB 3000MHz G.Skill Trident Z

Samsung 870 Evo (Boot Drive)

KFA2 GTX 1070ti

 

[wseaton]

Big question here: did you verify their performance when you first installed them and this problem has recently cropped up, or........you are just now getting around to testing it and seeing there's an issue? Honesty counts.

 

 I used to like Intel onboard RAID / RST and spinners because while it had mediocre performance it was light years more reliable than lower end HBAs or RAID cards. I will happily argue this point with balled fists with any so called storage engineer, and I have. Intel RST / RAID  *was* a quick and dirty and respectably reliable way to give fault tolerance to a critical workstation or lightweight server, and it was free. I wish more people had used it , especially in the business world. Beats being down for days waiting for a new HD sweating over the loss of the desktop full of locally stored Excel files with no backups.

 

However, I have had nothing but issues with Intel onboard RAID and SATA SSD's on multiple PC's and small servers. Even if the SSD is sitting in there solo and RAID is enabled read performance is crushed. Once I flip the BIOS back to AHCI performance goes back to normal. So, the issue is not with RAID topography but some issue with RST itself.  Last I checked Intel has dropped RST support for Windows Server, and this might be an indication of Intel losing interest in RST. Intel is still pushing VROC, not that I've ever encountered anybody using it. I still love Intel SSD storage, but RST is now dead to me.

 

Using native Windows software RAID and running the drives in AHCI mode improved read performance, but shifted the problem to writes. Sorry I don't have a solution, only to confirm it's an issue. My experience is it takes a beefy dedicated RAID adapter like a H700 or better to not throttle SATA SSD performance. 

 

Sidebar, but I've encountered many laptops from mostly Dell using SATA SSD with intel RST RAID enabled from the factory, and it has the same problem. I'm assuming the RAID mode is enabled as part of factory drive cloning, and the tech was too lazy to flip it back to AHCI. 

 

 

[taiyra]

3 hours ago, wseaton said:

did you verify their performance when you first installed them and this problem has recently cropped up

I did verify the performance when I first installed it. Read was about 1.4GB/s if I remember correctly.

A few months ago was the last time I checked, same speed. So it was working fine for a long time.

I noticed the issues just a few days ago. And thats what I don't get since I didn't change anything on the system as far as I know.

And only Seq Read seems to be affected since 4KiB gives good results.

 

To Intel RST: I didn't have the Software installed until the problem started to show up. Just enabled RAID in BIOS and configured the array in that pre-boot window. (not sure whats the name of it).