add a doc on environment variables that can be used to tweak lotus

documentation/en/.library.json

@@ -67,6 +67,12 @@
           "slug": "en+setup-troubleshooting",
           "github": "en/setup-troubleshooting.md",
           "value": null
+        },
+        {
+          "title": "Environment Variables",
+          "slug": "en+env-vars",
+          "github": "en/environment-vars.md",
+          "value": null
         }
       ]
     },

documentation/en/environment-vars.md

@@ -0,0 +1,60 @@
+# Lotus Environment Variables
+
+## Building
+
+## Common
+
+The environment variables are common across most lotus binaries.
+
+### `LOTUS_FD_MAX`
+
+Sets the file descriptor limit for the process. This should be set high (8192
+or higher) if you ever notice 'too many open file descriptor' errors.
+
+### `LOTUS_JAEGER`
+
+This can be set to enable jaeger trace reporting. The value should be the url
+of the jaeger trace collector, the default for most jaeger setups should be
+`localhost:6831`.
+
+### `LOTUS_DEV`
+
+If set to a non-empty value, certain parts of the application will print more
+verbose information to aid in development of the software. Not recommended for
+end users.
+
+## Lotus Daemon
+
+### `LOTUS_PATH`
+
+Sets the location for the lotus daemon on-disk repo. If left empty, this defaults to `~/.lotus`.
+
+### `LOTUS_SKIP_GENESIS_CHECK`
+
+Can be set to `_yes_` if you wish to run a lotus network with a different
+genesis than the default one built into your lotus binary.
+
+### `LOTUS_CHAIN_TIPSET_CACHE`
+
+Sets the cache size for the chainstore tipset cache. The default value is 8192,
+but if your usage of the lotus API involves frequent arbitrary tipset lookups,
+you may want to increase this.
+
+### `LOTUS_CHAIN_INDEX_CACHE`
+
+Sets the cache size for the chainstore epoch index cache. The default value is 32768,
+but if your usage of the lotus API involves frequent deep chain lookups for
+block heights that are very far from the current chain height, you may want to
+increase this.
+
+
+
+## Lotus Miner
+
+A number of environment variables are respected for configuring the behavior of the filecoin proving subsystem. For more details on those [see here](https://github.com/filecoin-project/rust-fil-proofs/#settings).
+
+### `LOTUS_MINER_PATH`
+
+Sets the location for the lotus miners on-disk repo. If left empty, this defaults to `~/.lotusminer`.
+
+

lib/ulimit/ulimit.go

@@ -28,14 +28,19 @@ const minFds = 2048
 // default max file descriptor limit.
 const maxFds = 16 << 10
 
-// userMaxFDs returns the value of IPFS_FD_MAX
+// userMaxFDs returns the value of LOTUS_FD_MAX
 func userMaxFDs() uint64 {
-	// check if the IPFS_FD_MAX is set up and if it does
+	// check if the LOTUS_FD_MAX is set up and if it does
 	// not have a valid fds number notify the user
-	if val := os.Getenv("IPFS_FD_MAX"); val != "" {
+	val := os.Getenv("LOTUS_FD_MAX")
+	if val == "" {
+		val = os.Getenv("IPFS_FD_MAX")
+	}
+
+	if val != "" {
 		fds, err := strconv.ParseUint(val, 10, 64)
 		if err != nil {
-			log.Errorf("bad value for IPFS_FD_MAX: %s", err)
+			log.Errorf("bad value for LOTUS_FD_MAX: %s", err)
 			return 0
 		}
 		return fds
@@ -44,7 +49,7 @@ func userMaxFDs() uint64 {
 }
 
 // ManageFdLimit raise the current max file descriptor count
-// of the process based on the IPFS_FD_MAX value
+// of the process based on the LOTUS_FD_MAX value
 func ManageFdLimit() (changed bool, newLimit uint64, err error) {
 	if !supportsFDManagement {
 		return false, 0, nil
@@ -93,7 +98,7 @@ func ManageFdLimit() (changed bool, newLimit uint64, err error) {
 
 		if newLimit < userLimit {
 			err = fmt.Errorf(
-				"failed to raise ulimit to IPFS_FD_MAX (%d): set to %d",
+				"failed to raise ulimit to LOTUS_FD_MAX (%d): set to %d",
 				userLimit,
 				newLimit,
 			)