We’ve recently undertaken a project that involves replication between Equallogic iSCSI SANs. Using Exinda appliances, the objective is to use acceleration (WAN memory) to improve replication performance, whilst using shaping to ensure that other business critical applications get priority during the day.
We may look to using schedules to give the replication high priority access over night and reduced during the day, whilst still allowing it to burst to 100% when the WAN isn’t being used for other activities.
iSCSI (Internet Small Computer System Interface) isn’t currently in the Exinda pre-defined applications list.
The components we identified for iSCSI applications are:
- iSCSI-target (general communication) on tcp port 3260
- iSCSI-system on tcp port 860 (note that this is an IANA port allocation, but the default and well-known port should be 3260)
- iSNS (Internet Storage Name Service) on tcp port 3205
We can define the individual applications via the GUI or the command line, then create an application group to cover it all off in a single policy.
(config) # application iSCSI-target port 3260 protocol tcp
(config) # application iSCSI-system port 3205 protocol tcp
(config) # application iSNS port 860 protocol tcp
(config) # applicationgrp iSCSI application iSCSI-target
(config) # applicationgrp iSCSI application iSCSI-system
(config) # applicationgrp iSCSI application iSNS
Then we can check all looks fine with:
# show applicationgrp iSCSI
Application Group: iSCSI
With this application definition, it’s now possible to set Exinda policies to provide visibility, Quality of Service and acceleration to this kind of traffic.