iSCSI SAN Block Storage Engineering
iSCSI Throughput and MPIO Calculator
Work out which ceiling binds first: the aggregate MPIO link budget, the storage media behind the LUN, or the per-I/O latency the queue depth leaves you.
Effective Throughput
1,200 MB/s
Throughput-Limited IOPS
19,200 IOPS
Per-I/O Latency Budget
1.67 ms
Binding Constraint
Storage Array Limited
What the model assumes
- A 10 Gbps path is treated as roughly 1,175 MB/s once Ethernet, IP and TCP framing overhead is removed, and paths are assumed to be evenly loaded by a round-robin policy.
- Throughput is the lower of the aggregate link budget and the media figure, because a SAN is bounded by whichever of the two saturates first.
- IOPS here is throughput divided by the block size, so it is the rate the bandwidth ceiling allows at that request size, not the media's random-access rating. The IOPS figures printed in the media dropdown are that separate random-access rating, and the model deliberately does not use them: at 64 KB requests an SSD array rated for six figures of small-block IOPS is still capped by its 1,200 MB/s.
- The latency budget applies Little's Law: at a given queue depth, sustaining the stated IOPS requires each I/O to complete inside that time. Media that is slower than the budget makes the queue, not the network, the constraint.
- Media figures are representative class values for planning, not vendor specifications for a particular drive or array.
Related guides
- iSCSI fundamentals: targets, LUNs and multipathing Why adding paths raises the ceiling and adding a bond does not.
- Unraid iSCSI target setup Choosing the backing store that has to hit the media figure above.
- iSCSI troubleshooting: login, timeout and path errors When the measured number is far below the modelled one, start here.
- iSCSI vs NFS vs SMB Whether multipathing is even available on the protocol you picked.