seaweedfs/go/topology/volume_layout.go
Chris Lu 50269b74ce add dataCenter option when assign file keys
add dataCenter option when starting volume servers
some work related to freeze a volume. Not tested yet.
2013-06-19 18:10:38 -07:00

152 lines
4.1 KiB
Go

package topology
import (
"code.google.com/p/weed-fs/go/storage"
"errors"
"fmt"
"math/rand"
)
type VolumeLayout struct {
repType storage.ReplicationType
vid2location map[storage.VolumeId]*VolumeLocationList
writables []storage.VolumeId // transient array of writable volume id
pulse int64
volumeSizeLimit uint64
}
func NewVolumeLayout(repType storage.ReplicationType, volumeSizeLimit uint64, pulse int64) *VolumeLayout {
return &VolumeLayout{
repType: repType,
vid2location: make(map[storage.VolumeId]*VolumeLocationList),
writables: *new([]storage.VolumeId),
pulse: pulse,
volumeSizeLimit: volumeSizeLimit,
}
}
func (vl *VolumeLayout) RegisterVolume(v *storage.VolumeInfo, dn *DataNode) {
if _, ok := vl.vid2location[v.Id]; !ok {
vl.vid2location[v.Id] = NewVolumeLocationList()
}
if vl.vid2location[v.Id].Add(dn) {
if len(vl.vid2location[v.Id].list) == v.RepType.GetCopyCount() {
if vl.isWritable(v) {
vl.writables = append(vl.writables, v.Id)
}
}
}
}
func (vl *VolumeLayout) isWritable(v *storage.VolumeInfo) bool {
return uint64(v.Size) < vl.volumeSizeLimit &&
v.Version == storage.CurrentVersion &&
!v.ReadOnly
}
func (vl *VolumeLayout) Lookup(vid storage.VolumeId) []*DataNode {
if location := vl.vid2location[vid]; location != nil {
return location.list
}
return nil
}
func (vl *VolumeLayout) PickForWrite(count int, dataCenter string) (*storage.VolumeId, int, *VolumeLocationList, error) {
len_writers := len(vl.writables)
if len_writers <= 0 {
fmt.Println("No more writable volumes!")
return nil, 0, nil, errors.New("No more writable volumes!")
}
if dataCenter == "" {
vid := vl.writables[rand.Intn(len_writers)]
locationList := vl.vid2location[vid]
if locationList != nil {
return &vid, count, locationList, nil
}
return nil, 0, nil, errors.New("Strangely vid " + vid.String() + " is on no machine!")
} else {
var vid storage.VolumeId
var locationList *VolumeLocationList
counter := 0
for _, v := range vl.writables {
volumeLocationList := vl.vid2location[v]
for _, dn := range volumeLocationList.list {
if dn.GetDataCenter().Id() == NodeId(dataCenter) {
counter++
if rand.Intn(counter) < 1 {
vid, locationList = v, volumeLocationList
}
}
}
}
return &vid, count, locationList, nil
}
return nil, 0, nil, errors.New("Strangely This Should Never Have Happened!")
}
func (vl *VolumeLayout) GetActiveVolumeCount(dataCenter string) int {
if dataCenter == "" {
return len(vl.writables)
}
counter := 0
for _, v := range vl.writables {
for _, dn := range vl.vid2location[v].list {
if dn.GetDataCenter().Id() == NodeId(dataCenter) {
counter++
}
}
}
return counter
}
func (vl *VolumeLayout) removeFromWritable(vid storage.VolumeId) bool {
for i, v := range vl.writables {
if v == vid {
fmt.Println("Volume", vid, "becomes unwritable")
vl.writables = append(vl.writables[:i], vl.writables[i+1:]...)
return true
}
}
return false
}
func (vl *VolumeLayout) setVolumeWritable(vid storage.VolumeId) bool {
for _, v := range vl.writables {
if v == vid {
return false
}
}
fmt.Println("Volume", vid, "becomes writable")
vl.writables = append(vl.writables, vid)
return true
}
func (vl *VolumeLayout) SetVolumeUnavailable(dn *DataNode, vid storage.VolumeId) bool {
if vl.vid2location[vid].Remove(dn) {
if vl.vid2location[vid].Length() < vl.repType.GetCopyCount() {
fmt.Println("Volume", vid, "has", vl.vid2location[vid].Length(), "replica, less than required", vl.repType.GetCopyCount())
return vl.removeFromWritable(vid)
}
}
return false
}
func (vl *VolumeLayout) SetVolumeAvailable(dn *DataNode, vid storage.VolumeId) bool {
if vl.vid2location[vid].Add(dn) {
if vl.vid2location[vid].Length() >= vl.repType.GetCopyCount() {
return vl.setVolumeWritable(vid)
}
}
return false
}
func (vl *VolumeLayout) SetVolumeCapacityFull(vid storage.VolumeId) bool {
return vl.removeFromWritable(vid)
}
func (vl *VolumeLayout) ToMap() interface{} {
m := make(map[string]interface{})
m["replication"] = vl.repType.String()
m["writables"] = vl.writables
//m["locations"] = vl.vid2location
return m
}