Merge pull request #324 from versity/auke/tcp_timeo_shorter

Shorten the default TCP_KEEPALIVE_TIMEOUT_MS to 24s

kmod/src/options.c

@@ -136,7 +136,7 @@ static void free_options(struct scoutfs_mount_options *opts)
 #define MIN_DATA_PREALLOC_BLOCKS	1ULL
 #define MAX_DATA_PREALLOC_BLOCKS	((unsigned long long)SCOUTFS_BLOCK_SM_MAX)
 
-#define DEFAULT_TCP_KEEPALIVE_TIMEOUT_MS	(60 * MSEC_PER_SEC)
+#define DEFAULT_TCP_KEEPALIVE_TIMEOUT_MS	(24 * MSEC_PER_SEC)
 
 static void init_default_options(struct scoutfs_mount_options *opts)
 {

utils/man/scoutfs.5

@@ -161,7 +161,7 @@ connection will wait for active TCP packets, before deciding that
 the connection is dead. This setting is per-mount and only changes
 the behavior of that mount.
 .sp
-The default value of this setting is 60000msec (60s). Any precision
+The default value of this setting is 24000msec (24s). Any precision
 beyond a whole second is likely unrealistic due to the nature of
 TCP keepalive mechanisms in the Linux kernel. Valid values are any
 value higher than 3000 (3s).
@@ -170,7 +170,8 @@ The TCP keepalive mechanism is complex and observing a lost connection
 quickly is important to maintain cluster stability. If the local
 network suffers from intermittent outages this option may provide
 some respite to overcome these outages without the cluster becoming
-desynchronized.
+desynchronized. Values above 30s are discouraged due to the negative
+effect on recovery from fencing.
 .SH VOLUME OPTIONS
 Volume options are persistent options which are stored in the super
 block in the metadata device and which apply to all mounts of the volume.