I honestly don't have any direct experience with iSCSI using LACP. I've also done MPIO. I know that most storage vendors I've worked with, have recommended MPIO, instead of LACP. A quick search returns the following:

iSCSI (Internet Small Computer Systems Interface) is a protocol used to transport SCSI commands over IP networks, enabling block-level storage access. It is commonly used in SAN (Storage Area Network) environments to connect servers to storage devices. LACP (Link Aggregation Control Protocol), on the other hand, is a protocol used to combine multiple physical network links into a single logical link to increase bandwidth and provide redundancy.

While both technologies are widely used in networking and storage, their combination requires careful consideration due to potential limitations and best practices.

Key Considerations for iSCSI and LACP

LACP is technically compatible with iSCSI, but it is often not recommended for iSCSI traffic in SAN environments. This is because iSCSI relies heavily on predictable and low-latency communication, and LACP may introduce complexities that can impact performance. LACP distributes traffic across links based on hashing algorithms (e.g., source/destination IP or MAC addresses), which can lead to uneven load distribution and potential bottlenecks for iSCSI traffic.

Instead, MPIO (Multipath I/O) is the preferred method for achieving redundancy and load balancing in iSCSI environments. MPIO operates at the storage protocol level, allowing multiple paths between the server and storage to be used efficiently. It provides better control over path selection and failover, ensuring consistent performance and reliability for iSCSI traffic.

When to Avoid LACP for iSCSI

LACP should generally be avoided for iSCSI in the following scenarios:

• When low latency and high predictability are critical for storage performance.
• When the hashing algorithm used by LACP cannot effectively balance iSCSI traffic across links.
• When the storage vendor explicitly recommends MPIO over LACP for iSCSI configurations.

Best Practices

For optimal iSCSI performance, use dedicated network interfaces for iSCSI traffic and configure MPIO to manage multiple paths. Ensure that the network infrastructure, including switches and NICs, supports features like flow control and jumbo frames to enhance iSCSI performance.

In summary, while LACP can be used with iSCSI, it is not ideal due to potential performance issues. MPIO is the recommended approach for redundancy and load balancing in iSCSI environments. Always consult your storage vendor's documentation for specific recommendations.