Brand New Build Slow SSD Cache Pool?

[mbc0]

Hi,

 

I have just built a second server and using a 2 disk SSD cache pool for the first time and it is dissapointingly slow so I am wondering if I haven't got it setup quite right as copying to the cache starts at 120mb/s and grinds to kb/s then speeds up to 30-40mb/s then down to kb/s etc. 

 

I am aware that it will write to RAM first (hence the maxed out speed initially) but I would expect an SSD cache to be faster? maybe I am expecting too much 🙂

 

Diags attached below during 15GB file write to cache,

 

Many Thanks!

 

M/B: ASRock X470 Taichi Version - s/n:

BIOS: American Megatrends Inc. Version P3.90. Dated: 01/10/2020

CPU: AMD Ryzen 5 3600X 6-Core @ 4000 MHz

HVM: Enabled

IOMMU: Enabled

Cache: 384 KiB, 3072 KiB, 32768 KiB

Memory: 16 GiB DDR4 (max. installable capacity 128 GiB)

Network: bond0: fault-tolerance (active-backup), mtu 1500
 eth0: 1000 Mbps, full duplex, mtu 1500

Kernel: Linux 4.19.107-Unraid x86_64

OpenSSL: 1.1.1d

 

 

unraid2-diagnostics-20200501-1130.zip

[JorgeB]

Though 30/40MB/s is still slow you're using slower TLC based SSDs (WD green is TLC, never heard of a Palit SSD, but should be similarly low end, and even if it isn't the pool will be limited by the slower device), they will never perform great, I recommended 3D TLC based, 860 EVO, MX500, WD Blue 3D, etc.

 

 

[mbc0]

21 minutes ago, johnnie.black said:

Though 30/40MB/s is still slow you're using slower TLC based SSDs (WD green is TLC, never heard of a Palit SSD, but should be similarly low end, and even if it isn't the pool will be limited by the slower device), they will never perform great, I recommended 3D TLC based, 860 EVO, MX500, WD Blue 3D, etc.

Yeah they are low end I realize that, I use 970 Pro NVME in my other server over 10gb/e and that is blinding.  

 

This is only really a "backup" server so no real need for lightning speeds just it is alot slower than expected! 

 

Thanks for your time

21 minutes ago, johnnie.black said: