Dell Acceleration Appliances for Databases - Manual (Page 58)

(See Creating RHEL Initiators in ION Accelerator for sample
multipath –ll
output.)
Setting the Node Session Timeout for iSCSI
If you are using the iSCSI protocol, you need to set the
node.session.timeo.replacement_timeout
value. This should be done for both HA and
standalone systems.
This should not be done while applications are using the iSCSI or dm-multipath devices.
The
node.session.timeo.replacement_timeout
setting controls the amount of time a path is
tried before it is failed. When using
dm-multipath
, a value of 15 seconds is safe. If your
applications require faster failovers, you may need to set the value lower, such as to 5 seconds.
To set this value so it can be used for both current and new sessions,
1. Edit the /etc/iscsid.conf file and set an appropriate value for
node.session.timeo.replacement_timeout
.
2. Log out of current sessions by running
iscsiadm -m session –u
.
3. Set the replacement timeout for currently discovered portals, as follows:
iscsiadm -m node -o update -n node.session.timeo.replacement_timeout -
v 15
4. Log in to the targets again:
iscsiadm -m node -T target -p IP -l
LINUX ISCSI INITIATOR NOTES
Below are some tips on using Linux iSCSI initiators with ION Accelerator.
• The
SCSI H:C:I:L
address assigned by a Linux initiator system consists of four
components: Host, Channel, Target ID and LUN. Of these components, only the LUN
number is assigned by the ION Accelerator system. The other three components are assigned
by the initiator system.
• An HBA reset can cause the first three components of an
H:C:I:L
address to change.
• An HBA reset can cause a new
/dev/sd*
device node to be assigned to a path.
• A LUN rescan initiated by the
rescan-scsi-bus.sh
script changes neither the
H:C:I:L
iSCSI address nor the
/dev/sd*
device node assigned to a path.
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