Transfer Speeds Very Erratic

[edenite]

I'm setting up a SOFS with 40TB storage. I plan to setup 1 node and get the data on it, then add another node for replication. But i'm stuck on getting the devices setup correctly. I have a 10GB network. My array is using Raid 5 / Adaptive Read Ahead / Write Through / 64 KB / Cache Enabled.

I tried various device sizes but ran into problems with the amount of ram on my system to account for the cache size needed. Starting over, I decided to do more testing so I created an 11TB device with 11GB Write-Back cache using 4096 sector size. I connected to the device with iSCSI initiator and formatted the disk with the default allocation unit size.

When I try to copy a file to the drive from over the network, the speed starts rockin at around 600 MB/s but then tanks to 1 MB/s or 0 MB/s after about 10 seconds. After about 10 seconds it goes back up to about 30 MB/s. It's all over the place.

When I try to copy a file to the drive from another drive on the server it is more stable but it fluctuates from about 140 MB/s to 0 MB/s every 10 seconds or so.

Please tell me my configuration is off because I know the software works like a charm otherwise.

[Michael (staff)]

Hello Edenite,
Actually file copying is not the best way to check the storage performance.
Here is the great article about it: https://blogs.technet.microsoft.com/jos ... o-instead/

As it is recommended, please use DISKSPD utility to check storage performance: https://gallery.technet.microsoft.com/D ... e-6cd2f223
Check the local storage disk performance, create Standalone device, connect it in MS iSCSI Initiator on StarWind host (by 127.0.0.1 ip address), create Volume and test its performance as well.
Also, before running the tests. please set the following RAID settings if you have spindled disks: Disk cache policy: default; Read policy: read ahead; Write policy: write back; Stripe size: 64KB.
Let us know about the results.