Lustre 1.6 Operations Manual

31.2.4 RapidArray LND
The RapidArray LND (ralnd) is connection-based and uses the acceptor to establish
connections with its peers. It is limited to a single instance, which uses all (both)
RapidArray devices present. It load balances over them using the XOR of the source
and destination NIDs to determine which device to use for communication.
The address-within-network is determined by the address of the single IP interface
that may be specified by the "networks" module parameter. If this is omitted, then
the first non-loopback IP interface that is up is used instead.
Variable
n_connd
(4)
min_reconnect_interv
al
(1,W)
max_reconnect_interv
al
(60,W)
timeout
(30,W)
ntx
(64)
ntx_nblk
(256)
fma_cq_size
(8192)
max_immediate
(2048,W)
Description
Sets the number of connection daemons.
Minimum connection retry interval (in seconds). After a failed
connection attempt, this sets the time that must elapse before the
first retry. As connections attempts fail, this time is doubled on
each successive retry, up to a maximum of the
max_reconnect_interval option.
Maximum connection retry interval (in seconds).
Time (in seconds) that communications may be stalled before the
LND completes them with failure.
Number of "normal" message descriptors for locally-initiated
communications that may block for memory (callers block when
this pool is exhausted).
Number of "reserved" message descriptors for communications
that may not block for memory. This pool must be sized large
enough so it is never exhausted.
Number of entries in the RapidArray FMA completion queue to
allocate. It should be increased if the ralnd starts to issue warnings
that the FMA CQ has overflowed. This is only a performance issue.
Size (in bytes) of the smallest message that will be RDMA’d, rather
than being included as immediate data in an FMA. All messages
greater than 6912 bytes must be RDMA’d (FMA limit).
Chapter 31 Configuration Files and Module Parameters (man5) 31-11