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Veritas InfoScale™ 7.3 Release Notes - Linux

Last Published: 2018-01-04

Product(s): InfoScale & Storage Foundation (7.3, 7.3, 7.3, 7.3)

LLT adaptive window parameter

[Linux only]

The adaptive window parameter enables LLT to control and automatically adjust the value of window size. It provides flexibility in monitoring and setting the maximum number of un-ACKed packets that LLT will put in flight.

In this release, the adaptive window parameter (LLT_ENABLE_AWINDOW) is enabled by default for port 5 (cfs) and port 24(cvm) in the /etc/sysconfig/llt file. You can manually enable adaptive window for other ports by changing the value of the LLT_AW_PORT_LIST parameter.

If you want to set window size for ports other than those listed in the LLT_AW_PORT_LIST parameter, you can set the window size by appending the /etc/llttab file with the values: Set-flow window: <value>

To disable the adaptive window feature, the value of the LLT_ENABLE_AWINDOW parameter should be set to zero.

To apply the adaptive window feature port-wise:

See the value of the LLT_AW_PORT_LIST parameter in /etc/sysconfig/llt file to get the list of ports for which the adaptive window feature is enabled.
For example, LLT_AW_PORT_LIST='"5,24"' shows that both ports are enabled.
To enable adaptive window for ports other than 5 and 24, add the port numbers in LLT_AW_PORT_LIST separated by comma.
For example: LLT_AW_PORT_LIST=: '"5,24,0,1,5,14"' shows that adaptive window is enabled for the listed port.
To disable the adaptive window feature for any of these two ports, remove the specific port from this parameter.
For example, LLT_AW_PORT_LIST='"5"' shows that adaptive window is disabled on port 24.

To see the current window size for each port, use the /opt/VRTSllt/lltshow -n <remote-nid> command and check the value of "Current AWindow".

For example:

/opt/VRTSllt/lltshow -n remote-nid

.
.
port [24]:
   lastacked= 0x1e528a  nextseq= 0x1e528b  recv_seq= 0x1e8b2e  
              nextrxseq= 0x1e8b2f
   xmit_head= 0x0  xmit_tail= 0x0 xmit_next= 0x0
   xmit_count= 0  ack_count= 2
   recv_reseq= 0x0  recv_reseq_cnt= 0 oos= 0
   nxtlink= 0 linkxmits= 24
   Current AWindow: 450
   rdma xmit_head= 0x0  rdma xmit_tail= 0x0 rdma xmit_next= 0x0
   rdma xmit_count= 0  rdma onwire_cnt= 0
   rdma nxtlink= 0 rdma linkxmits= 0
   rdma nexttxseq= 1987309  rdma: 450