About a month ago, I lost my RAID 5 array, one drive died and another corrupted during the rebuild. I was able to recover much of it and I have since moved on.

Before the loss, I had 4x2TB Samsung F4 Ecogreen drives running in RAID 5 controlled by my A5M88-M Motherboard and things worked great. With my recent ISP upgrade, I was seeing DL speeds of 25MB/s with no issues.

Post loss, I decided to upgrade, and with the age of my server, use a RAID controller so I could migrate if I lost my Mobo. I am currently running an LSI MegaRAID 9266-8i and 8x4TB WD RED NAS drives running in RAID 6. I am still seeing the same DL speeds, but with uTorrent 2.2.1 (same as before) I am running into Disk Overloaded errors.

I have messed around with the Cache settings quite a bit. I’ve tried 512, 1024 & 1536 MB and increasing this just delays the error until the cache fills up. If I disable writing to cache, I obviously don’t get disk overload errors, but this throttles my DL speed to <500kB/s.

This leads me to believe it has something to do with the drive’s write speed. So I ran CrystalDiskMark to check performance, but I admittedly do not know how to interpret the results, but I am pretty sure everything below the first round is very poor.

5 – 4GiB Setting

Seq Q32T1: Read 1048.7 MB/s Write 258.5 MB/s
4KiB Q8T8: Read 11.64 MB/s Write 1.178 MB/s
4KiB Q32T1: Read 8.795 MB/s Write 1.143 MB/s
4KiB Q1T1: Read 0.344 MB/s Write 0.045 MB/s

As for the RAID configuration I can provide the following information:

All drives are reporting 6.0Gbps negotiated link speeds
Status is optimal
I do not have a battery backup, so the write policy is set to Write Through
Read policy is set to Always Read Ahead
Strip Size is 64kB
Disk Cache Policy is disabled

What could be causing the issue? I have read it may be antivirus. I am using Windows Defender only. I am running Server 2008 R2.

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