server: Move all the top level files into cmd folder. (#2490)

This change brings a change which was done for the 'mc'
package to allow for clean repo and have a cleaner
github drop in experience.

cmd/server-rlimit-nix.go

@@ -0,0 +1,91 @@
+//  +build !windows,!plan9
+
+/*
+ * Minio Cloud Storage, (C) 2016 Minio, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package cmd
+
+import (
+	"syscall"
+
+	"github.com/minio/minio/pkg/sys"
+)
+
+// For all unixes we need to bump allowed number of open files to a
+// higher value than its usual default of '1024'. The reasoning is
+// that this value is too small for a server.
+func setMaxOpenFiles() error {
+	var rLimit syscall.Rlimit
+	err := syscall.Getrlimit(syscall.RLIMIT_NOFILE, &rLimit)
+	if err != nil {
+		return err
+	}
+	// Set the current limit to Max, it is usually around 4096.
+	// TO increase this limit further user has to manually edit
+	// `/etc/security/limits.conf`
+	rLimit.Cur = rLimit.Max
+	err = syscall.Setrlimit(syscall.RLIMIT_NOFILE, &rLimit)
+	if err != nil {
+		return err
+	}
+	err = syscall.Getrlimit(syscall.RLIMIT_NOFILE, &rLimit)
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+// Set max memory used by minio as a process, this value is usually
+// set to 'unlimited' but we need to validate additionally to verify
+// if any hard limit is set by the user, in such a scenario would need
+// to reset the global max cache size to be 80% of the hardlimit set
+// by the user. This is done to honor the system limits and not crash.
+func setMaxMemory() error {
+	var rLimit syscall.Rlimit
+	err := syscall.Getrlimit(syscall.RLIMIT_AS, &rLimit)
+	if err != nil {
+		return err
+	}
+	// Set the current limit to Max, it is default 'unlimited'.
+	// TO decrease this limit further user has to manually edit
+	// `/etc/security/limits.conf`
+	rLimit.Cur = rLimit.Max
+	err = syscall.Setrlimit(syscall.RLIMIT_AS, &rLimit)
+	if err != nil {
+		return err
+	}
+	err = syscall.Getrlimit(syscall.RLIMIT_AS, &rLimit)
+	if err != nil {
+		return err
+	}
+	// Validate if rlimit memory is set to lower
+	// than max cache size. Then we should use such value.
+	if uint64(rLimit.Cur) < globalMaxCacheSize {
+		globalMaxCacheSize = (80 / 100) * uint64(rLimit.Cur)
+	}
+
+	// Make sure globalMaxCacheSize is less than RAM size.
+	stats, err := sys.GetStats()
+	if err != nil && err != sys.ErrNotImplemented {
+		// sys.GetStats() is implemented only on linux. Ignore errors
+		// from other OSes.
+		return err
+	}
+	if err == nil && stats.TotalRAM < globalMaxCacheSize {
+		globalMaxCacheSize = (80 / 100) * stats.TotalRAM
+	}
+	return nil
+}