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package shell
import (
"context"
"flag"
"fmt"
"io"
"math"
"github.com/chrislusf/seaweedfs/weed/pb/master_pb"
"github.com/chrislusf/seaweedfs/weed/storage/erasure_coding"
"github.com/chrislusf/seaweedfs/weed/storage/needle"
)
func init() {
commands = append(commands, &commandEcBalance{})
}
type commandEcBalance struct {
}
func (c *commandEcBalance) Name() string {
return "ec.balance"
}
func (c *commandEcBalance) Help() string {
return `balance all ec shards among volume servers
ec.balance [-c EACH_COLLECTION|<collection_name>] [-f] [-dataCenter <data_center>]
Algorithm:
For each type of volume server (different max volume count limit){
for each collection {
balanceEcVolumes()
}
}
func balanceEcVolumes(){
idealWritableVolumes = totalWritableVolumes / numVolumeServers
for {
sort all volume servers ordered by the number of local writable volumes
pick the volume server A with the lowest number of writable volumes x
pick the volume server B with the highest number of writable volumes y
if y > idealWritableVolumes and x +1 <= idealWritableVolumes {
if B has a writable volume id v that A does not have {
move writable volume v from A to B
}
}
}
}
`
}
func (c *commandEcBalance) Do(args []string, commandEnv *commandEnv, writer io.Writer) (err error) {
balanceCommand := flag.NewFlagSet(c.Name(), flag.ContinueOnError)
collection := balanceCommand.String("c", "EACH_COLLECTION", "collection name, or \"EACH_COLLECTION\" for each collection")
dc := balanceCommand.String("dataCenter", "", "only apply the balancing for this dataCenter")
applyBalancing := balanceCommand.Bool("f", false, "apply the balancing plan")
if err = balanceCommand.Parse(args); err != nil {
return nil
}
var resp *master_pb.VolumeListResponse
ctx := context.Background()
err = commandEnv.masterClient.WithClient(ctx, func(client master_pb.SeaweedClient) error {
resp, err = client.VolumeList(ctx, &master_pb.VolumeListRequest{})
return err
})
if err != nil {
return err
}
typeToNodes := collectVolumeServersByType(resp.TopologyInfo, *dc)
for _, volumeServers := range typeToNodes {
fmt.Printf("balanceEcVolumes servers %d\n", len(volumeServers))
if len(volumeServers) < 2 {
continue
}
if *collection == "EACH_COLLECTION" {
collections, err := ListCollectionNames(commandEnv, false, true)
if err != nil {
return err
}
fmt.Printf("balanceEcVolumes collections %+v\n", len(collections))
for _, c := range collections {
fmt.Printf("balanceEcVolumes collection %+v\n", c)
if err = balanceEcVolumes(commandEnv, c, *applyBalancing); err != nil {
return err
}
}
} else {
if err = balanceEcVolumes(commandEnv, *collection, *applyBalancing); err != nil {
return err
}
}
}
return nil
}
func balanceEcVolumes(commandEnv *commandEnv, collection string, applyBalancing bool) error {
ctx := context.Background()
fmt.Printf("balanceEcVolumes %s\n", collection)
// collect all ec nodes
allEcNodes, totalFreeEcSlots, err := collectEcNodes(ctx, commandEnv)
if err != nil {
return err
}
if totalFreeEcSlots < 1 {
return fmt.Errorf("no free ec shard slots. only %d left", totalFreeEcSlots)
}
// vid => []ecNode
vidLocations := make(map[needle.VolumeId][]*EcNode)
for _, ecNode := range allEcNodes {
for _, shardInfo := range ecNode.info.EcShardInfos {
vidLocations[needle.VolumeId(shardInfo.Id)] = append(vidLocations[needle.VolumeId(shardInfo.Id)], ecNode)
}
}
for vid, locations := range vidLocations {
// collect all ec nodes with at least one free slot
var possibleDestinationEcNodes []*EcNode
for _, ecNode := range allEcNodes {
if ecNode.freeEcSlot > 0 {
possibleDestinationEcNodes = append(possibleDestinationEcNodes, ecNode)
}
}
// calculate average number of shards an ec node should have for one volume
averageShardsPerEcNode := int(math.Ceil(float64(erasure_coding.TotalShardsCount) / float64(len(possibleDestinationEcNodes))))
fmt.Printf("vid %d averageShardsPerEcNode %+v\n", vid, averageShardsPerEcNode)
// check whether this volume has ecNodes that are over average
isOverLimit := false
for _, ecNode := range locations {
shardBits := findEcVolumeShards(ecNode, vid)
if shardBits.ShardIdCount() > averageShardsPerEcNode {
isOverLimit = true
fmt.Printf("vid %d %s has %d shards, isOverLimit %+v\n", vid, ecNode.info.Id, shardBits.ShardIdCount(), isOverLimit)
break
}
}
if isOverLimit {
if err := spreadShardsIntoMoreDataNodes(ctx, commandEnv, averageShardsPerEcNode, collection, vid, locations, possibleDestinationEcNodes, applyBalancing); err != nil {
return err
}
}
}
return nil
}
func spreadShardsIntoMoreDataNodes(ctx context.Context, commandEnv *commandEnv, averageShardsPerEcNode int, collection string, vid needle.VolumeId, existingLocations, possibleDestinationEcNodes []*EcNode, applyBalancing bool) error {
for _, ecNode := range existingLocations {
shardBits := findEcVolumeShards(ecNode, vid)
overLimitCount := shardBits.ShardIdCount() - averageShardsPerEcNode
for _, shardId := range shardBits.ShardIds() {
if overLimitCount <= 0 {
break
}
fmt.Printf("%s has %d overlimit, moving ec shard %d.%d\n", ecNode.info.Id, overLimitCount, vid, shardId)
err := pickOneEcNodeAndMoveOneShard(ctx, commandEnv, averageShardsPerEcNode, ecNode, collection, vid, shardId, possibleDestinationEcNodes, applyBalancing)
if err != nil {
return err
}
overLimitCount--
}
}
return nil
}
func pickOneEcNodeAndMoveOneShard(ctx context.Context, commandEnv *commandEnv, averageShardsPerEcNode int, existingLocation *EcNode, collection string, vid needle.VolumeId, shardId erasure_coding.ShardId, possibleDestinationEcNodes []*EcNode, applyBalancing bool) error {
sortEcNodes(possibleDestinationEcNodes)
for _, destEcNode := range possibleDestinationEcNodes {
if destEcNode.info.Id == existingLocation.info.Id {
continue
}
if destEcNode.freeEcSlot <= 0 {
continue
}
if findEcVolumeShards(destEcNode, vid).ShardIdCount() >= averageShardsPerEcNode {
continue
}
fmt.Printf("%s moves ec shard %d.%d to %s\n", existingLocation.info.Id, vid, shardId, destEcNode.info.Id)
err := moveOneShardToEcNode(ctx, commandEnv, existingLocation, collection, vid, shardId, destEcNode, applyBalancing)
if err != nil {
return err
}
destEcNode.freeEcSlot--
return nil
}
return nil
}
func moveOneShardToEcNode(ctx context.Context, commandEnv *commandEnv, existingLocation *EcNode, collection string, vid needle.VolumeId, shardId erasure_coding.ShardId, destinationEcNode *EcNode, applyBalancing bool) error {
fmt.Printf("moved ec shard %d.%d %s => %s\n", vid, shardId, existingLocation.info.Id, destinationEcNode.info.Id)
if !applyBalancing {
return nil
}
// ask destination node to copy shard and the ecx file from source node, and mount it
copiedShardIds, err := oneServerCopyEcShardsFromSource(ctx, commandEnv.option.GrpcDialOption, destinationEcNode, uint32(shardId), 1, vid, collection, existingLocation.info.Id)
if err != nil {
return err
}
// ask source node to delete the shard, and maybe the ecx file
return sourceServerDeleteEcShards(ctx, commandEnv.option.GrpcDialOption, vid, existingLocation.info.Id, copiedShardIds)
}
func findEcVolumeShards(ecNode *EcNode, vid needle.VolumeId) erasure_coding.ShardBits {
for _, shardInfo := range ecNode.info.EcShardInfos {
if needle.VolumeId(shardInfo.Id) == vid {
return erasure_coding.ShardBits(shardInfo.EcIndexBits)
}
}
return 0
}
|
