What are the maximum Fibre Channel (FC) queue depth settings per port for each single controller active/active configuration?
Applies to
- Fibre Channel
- FAS systems
Answer
The maximum number of hosts that can connect to a single FC port on a controller. Connecting the maximum number of hosts is generally not recommended, and you might need to tune the FC queue depths on the host to achieve this maximum value. Queue depth is the number of I/O requests (SCSI commands) that can be queued at one time on a storage controller. In a configuration with multiple initiators (hosts), all hosts should have similar queue depths. This prevents hosts with small queue depths from being starved by hosts with large queue depths.
See the following documentation for detailed information about the maximum FC queue depth:
- Fibre Channel and iSCSI Configuration Guide for the Data ONTAP 8.0 Release Family
- Fibre Channel and iSCSI Configuration Guide for the Data ONTAP 7.2 and Earlier Release Families
- Fibre Channel and iSCSI Configuration Guide for the Data ONTAP 7.3 Release Family
Example:
The older X1028 card has a maximum queue depth of 491, while the X1033A card has a maximum queue depth of 1966. These queue depth numbers are the maximum that the host can handle. Queue depths limits on the filer are always set to be as large as the hardware can accommodate. The host side queue depth is the only setting which can be tuned.
Additional Information
Related Links:
- Technical Report: NetApp Storage Controllers and Fibre Channel Queue Depth
- Setting queue depths on AIX hosts
- Setting queue depths on HP-UX hosts
- Setting queue depths on Solaris hosts
- Setting queue depths on VMware hosts
- Setting queue depths on Windows hosts
- Clustered Data ONTAP® 8.2 has a target port queue depth of 2048. For more information, see the Clustered Data ONTAP® 8.2 SAN Configuration Guide.