Installation guide

Chapter 21. Online Storage Management
122
• node_name
• port_name
•
dev_loss_tmo — number of seconds to wait before marking a link as "bad". Once a link is
marked bad, I/O running on its corresponding path (along with any new I/O on that path) will be
failed.
The default dev_loss_tmo value varies, depending on which driver/device is used. If a Qlogic
adapter is used, the default is 35 seconds, while if an Emulex adapter is used, it is 30 seconds.
The dev_loss_tmo value can be changed via the scsi_transport_fc module parameter
dev_loss_tmo, although the driver can override this timeout value.
The maximum dev_loss_tmo value is 600 seconds. If dev_loss_tmo is set to zero or any
value greater than 600, the driver's internal timeouts will be used instead.
•
fast_io_fail_tmo — length of time to wait before failing I/O executed when a link problem is
detected. I/O that reaches the driver will fail. If I/O is in a blocked queue, it will not be failed until
dev_loss_tmo expires and the queue is unblocked.
Host: /sys/class/fc_host/hostH/
• port_id
•
issue_lip — instructs the driver to rediscover remote ports.
21.1.2. Native Fibre Channel Drivers and Capabilities
Red Hat Enterprise Linux 6 ships with the following native fibre channel drivers:
• lpfc
• qla2xxx
• zfcp
• mptfc
Table 21.1, “Fibre-Channel API Capabilities” describes the different fibre-channel API capabilities of
each native Red Hat Enterprise Linux 6 driver. X denotes support for the capability.
Table 21.1. Fibre-Channel API Capabilities
lpfc qla2xxx zfcp mptfc
Transport
port_id
X X X X
Transport
node_name
X X X X
Transport
port_name
X X X X
Remote Port
dev_loss_tmo
X X X X
Remote Port
fast_io_fail_tmo
X X
1
X
2
Host port_id X X X X