minio/cmd/xl-v1.go
Harshavardhana 7765081db7 cache: Increasing caching GC percent from 20 to 50. (#4041)
Previous value was set to avoid large cache value build
up but we can clearly see this can cause lots of GC
pauses which can lead to significant drop in performance.

Change this value to 50% and decrease the value to 25%
once the 75% cache size is used. To have a larger
window for GC pauses.

Another change is to only allow caching if a server has
more than 24GB of RAM instead of 8GB.
2017-04-15 02:16:49 -07:00

268 lines
7.9 KiB
Go

/*
* 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 (
"fmt"
"runtime/debug"
"sort"
"sync"
humanize "github.com/dustin/go-humanize"
"github.com/minio/minio/pkg/disk"
"github.com/minio/minio/pkg/objcache"
)
// XL constants.
const (
// Format config file carries backend format specific details.
formatConfigFile = "format.json"
// Format config tmp file carries backend format.
formatConfigFileTmp = "format.json.tmp"
// XL metadata file carries per object metadata.
xlMetaJSONFile = "xl.json"
// Uploads metadata file carries per multipart object metadata.
uploadsJSONFile = "uploads.json"
// Represents the minimum required RAM size to enable caching.
minRAMSize = 24 * humanize.GiByte
// Maximum erasure blocks.
maxErasureBlocks = 16
// Minimum erasure blocks.
minErasureBlocks = 4
)
// xlObjects - Implements XL object layer.
type xlObjects struct {
mutex *sync.Mutex
storageDisks []StorageAPI // Collection of initialized backend disks.
dataBlocks int // dataBlocks count caculated for erasure.
parityBlocks int // parityBlocks count calculated for erasure.
readQuorum int // readQuorum minimum required disks to read data.
writeQuorum int // writeQuorum minimum required disks to write data.
// ListObjects pool management.
listPool *treeWalkPool
// Object cache for caching objects.
objCache *objcache.Cache
// Object cache enabled.
objCacheEnabled bool
}
// list of all errors that can be ignored in tree walk operation in XL
var xlTreeWalkIgnoredErrs = append(baseIgnoredErrs, errDiskAccessDenied, errVolumeNotFound, errFileNotFound)
// newXLObjectLayer - initialize any object layer depending on the number of disks.
func newXLObjectLayer(storageDisks []StorageAPI) (ObjectLayer, error) {
// Initialize XL object layer.
objAPI, err := newXLObjects(storageDisks)
fatalIf(err, "Unable to initialize XL object layer.")
// Initialize and load bucket policies.
err = initBucketPolicies(objAPI)
fatalIf(err, "Unable to load all bucket policies.")
// Initialize a new event notifier.
err = initEventNotifier(objAPI)
fatalIf(err, "Unable to initialize event notification.")
// Success.
return objAPI, nil
}
// newXLObjects - initialize new xl object layer.
func newXLObjects(storageDisks []StorageAPI) (ObjectLayer, error) {
if storageDisks == nil {
return nil, errInvalidArgument
}
readQuorum := len(storageDisks) / 2
writeQuorum := len(storageDisks)/2 + 1
// Load saved XL format.json and validate.
newStorageDisks, err := loadFormatXL(storageDisks, readQuorum)
if err != nil {
return nil, fmt.Errorf("Unable to recognize backend format, %s", err)
}
// Calculate data and parity blocks.
dataBlocks, parityBlocks := len(newStorageDisks)/2, len(newStorageDisks)/2
// Initialize list pool.
listPool := newTreeWalkPool(globalLookupTimeout)
// Initialize xl objects.
xl := &xlObjects{
mutex: &sync.Mutex{},
storageDisks: newStorageDisks,
dataBlocks: dataBlocks,
parityBlocks: parityBlocks,
listPool: listPool,
}
// Get cache size if _MINIO_CACHE environment variable is set.
var maxCacheSize uint64
if !globalXLObjCacheDisabled {
maxCacheSize, err = GetMaxCacheSize()
errorIf(err, "Unable to get maximum cache size")
// Enable object cache if cache size is more than zero
xl.objCacheEnabled = maxCacheSize > 0
}
// Check if object cache is enabled.
if xl.objCacheEnabled {
// Initialize object cache.
objCache, oerr := objcache.New(maxCacheSize, objcache.DefaultExpiry)
if oerr != nil {
return nil, oerr
}
objCache.OnEviction = func(key string) {
debug.FreeOSMemory()
}
xl.objCache = objCache
}
// Initialize meta volume, if volume already exists ignores it.
if err = initMetaVolume(xl.storageDisks); err != nil {
return nil, fmt.Errorf("Unable to initialize '.minio.sys' meta volume, %s", err)
}
// Figure out read and write quorum based on number of storage disks.
// READ and WRITE quorum is always set to (N/2) number of disks.
xl.readQuorum = readQuorum
xl.writeQuorum = writeQuorum
// If the number of offline servers is equal to the readQuorum
// (i.e. the number of online servers also equals the
// readQuorum), we cannot perform quick-heal (no
// write-quorum). However reads may still be possible, so we
// skip quick-heal in this case, and continue.
offlineCount := len(newStorageDisks) - diskCount(newStorageDisks)
if offlineCount == readQuorum {
return xl, nil
}
// Do a quick heal on the buckets themselves for any discrepancies.
return xl, quickHeal(xl.storageDisks, xl.writeQuorum, xl.readQuorum)
}
// Shutdown function for object storage interface.
func (xl xlObjects) Shutdown() error {
// Add any object layer shutdown activities here.
for _, disk := range xl.storageDisks {
// This closes storage rpc client connections if any.
// Otherwise this is a no-op.
if disk == nil {
continue
}
disk.Close()
}
return nil
}
// byDiskTotal is a collection satisfying sort.Interface.
type byDiskTotal []disk.Info
func (d byDiskTotal) Len() int { return len(d) }
func (d byDiskTotal) Swap(i, j int) { d[i], d[j] = d[j], d[i] }
func (d byDiskTotal) Less(i, j int) bool {
return d[i].Total < d[j].Total
}
// getDisksInfo - fetch disks info across all other storage API.
func getDisksInfo(disks []StorageAPI) (disksInfo []disk.Info, onlineDisks int, offlineDisks int) {
disksInfo = make([]disk.Info, len(disks))
for i, storageDisk := range disks {
if storageDisk == nil {
// Storage disk is empty, perhaps ignored disk or not available.
offlineDisks++
continue
}
info, err := storageDisk.DiskInfo()
if err != nil {
errorIf(err, "Unable to fetch disk info for %#v", storageDisk)
if isErr(err, baseErrs...) {
offlineDisks++
continue
}
}
onlineDisks++
disksInfo[i] = info
}
// Success.
return disksInfo, onlineDisks, offlineDisks
}
// returns sorted disksInfo slice which has only valid entries.
// i.e the entries where the total size of the disk is not stated
// as 0Bytes, this means that the disk is not online or ignored.
func sortValidDisksInfo(disksInfo []disk.Info) []disk.Info {
var validDisksInfo []disk.Info
for _, diskInfo := range disksInfo {
if diskInfo.Total == 0 {
continue
}
validDisksInfo = append(validDisksInfo, diskInfo)
}
sort.Sort(byDiskTotal(validDisksInfo))
return validDisksInfo
}
// Get an aggregated storage info across all disks.
func getStorageInfo(disks []StorageAPI) StorageInfo {
disksInfo, onlineDisks, offlineDisks := getDisksInfo(disks)
// Sort so that the first element is the smallest.
validDisksInfo := sortValidDisksInfo(disksInfo)
if len(validDisksInfo) == 0 {
return StorageInfo{
Total: -1,
Free: -1,
}
}
// Return calculated storage info, choose the lowest Total and
// Free as the total aggregated values. Total capacity is always
// the multiple of smallest disk among the disk list.
storageInfo := StorageInfo{
Total: validDisksInfo[0].Total * int64(onlineDisks) / 2,
Free: validDisksInfo[0].Free * int64(onlineDisks) / 2,
}
storageInfo.Backend.Type = Erasure
storageInfo.Backend.OnlineDisks = onlineDisks
storageInfo.Backend.OfflineDisks = offlineDisks
return storageInfo
}
// StorageInfo - returns underlying storage statistics.
func (xl xlObjects) StorageInfo() StorageInfo {
storageInfo := getStorageInfo(xl.storageDisks)
storageInfo.Backend.ReadQuorum = xl.readQuorum
storageInfo.Backend.WriteQuorum = xl.writeQuorum
return storageInfo
}