ISCSI and Windows Server 2019

iSCSI as a protocol is not limiting performance or latency on spindle (HDD) drives. It may limit on SSD and will limit on NVMe.

The performance in this case depends on:

1) Physical storage. You can increase amount of disk in RAID and use RAID10 for the best one. Video streaming uses large blocks, so properly aligned stripe size may also help.

2) Network between nodes. To eliminate network bottleneck, use 1 GbE or better 10 GbE connection. If you have multiple 1 GbE links, configure multipathing (mpio) and don’t use LACP (NIC teaming) for iSCSI. Here explanation: LACP vs MPIO

3) In some cases, adding additional iSCSI sessions per link may also increase performance.

4) Windows iSCSI Target is also not the quickest one, but it shouldn’t be a bottleneck for HDDs.