Qlogic HP driver in an Active/Active Setting
If you have an IO bound system you might want to try to use dual fibercards in an active/active setting. This is usually done by adding some SAN software like EMC powerpath or Securepath or Multipath. If you are using standard Qlogic cards you might be abel to set this up in an active/active configuration as well. This way we should be abel to push twice as much IO through each node. Please see this article by HP:
1. Install HP Proliant Support Pack (PSP)
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options qla2xxx ql2xmaxqdepth=16 qlport_down_retry=30 ql2xloginretrycount=30 ql2xfailover=1 ql2xlbType=2 ql2xautorestore=0x20
…
3. Create a new initrd
/opt/hp/src/hp_qla2x00src/make_initrd
4. Edit you driver (/etc/hp_qla2x00.conf)
qdepth = 16port_down_retry_count = 30
login_retry_count = 30
failover = 1
load_balancing = 2
auto_restore = 0x20
5. Boot the server/servers
The parameter ql2xlbType defines which method of load balancing you want to use:
0 (None) - Expose luns on the first active path and make them the preferred path or the first active optimize path and make them the preferred path (storages: MSA A/A and EVA A/A).
1 (Static load balancing) - Distribute and expose the LUNs across the active optimize port(s) or active un-optimize port(s) and HBA(s).
2 (Least outstanding I/O) - send command to the path with the lowest I/O count.
3 (Least Service time) - Send request to the path with the shortest execution time. Default: 0
- Endret /etc/hp_qla2x00.conf:
qdepth = 16
port_down_retry_count = 30
login_retry_count = 30
failover = 1
load_balancing = 2
auto_restore = 0x20
