gsh-digital-services/seaweedFS
5
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Unify the re-balancing logic for ec.encode with ec.balance. (#6339)

Browse Source 
Among others, this enables recent changes related to topology aware
re-balancing at EC encoding time.
This commit is contained in:
Lisandro Pin
2024-12-10 22:30:13 +01:00
committed by GitHub
parent ff1392f7f4
commit 8c82c037b9
6 changed files with 159 additions and 139 deletions
Download Patch File Download Diff File Expand all files Collapse all files

68
weed/shell/command_ec_balance.go
View File

@@ -24,73 +24,7 @@ func (c *commandEcBalance) Help() string {
ec.balance [-c EACH_COLLECTION|<collection_name>] [-force] [-dataCenter <data_center>] [-shardReplicaPlacement <replica_placement>]
Algorithm:
func EcBalance() {
for each collection:
balanceEcVolumes(collectionName)
for each rack:
balanceEcRack(rack)
}
func balanceEcVolumes(collectionName){
for each volume:
doDeduplicateEcShards(volumeId)
tracks rack~shardCount mapping
for each volume:
doBalanceEcShardsAcrossRacks(volumeId)
for each volume:
doBalanceEcShardsWithinRacks(volumeId)
}
// spread ec shards into more racks
func doBalanceEcShardsAcrossRacks(volumeId){
tracks rack~volumeIdShardCount mapping
averageShardsPerEcRack = totalShardNumber / numRacks // totalShardNumber is 14 for now, later could varies for each dc
ecShardsToMove = select overflown ec shards from racks with ec shard counts > averageShardsPerEcRack
for each ecShardsToMove {
destRack = pickOneRack(rack~shardCount, rack~volumeIdShardCount, ecShardReplicaPlacement)
destVolumeServers = volume servers on the destRack
pickOneEcNodeAndMoveOneShard(destVolumeServers)
}
}
func doBalanceEcShardsWithinRacks(volumeId){
racks = collect all racks that the volume id is on
for rack, shards := range racks
doBalanceEcShardsWithinOneRack(volumeId, shards, rack)
}
// move ec shards
func doBalanceEcShardsWithinOneRack(volumeId, shards, rackId){
tracks volumeServer~volumeIdShardCount mapping
averageShardCount = len(shards) / numVolumeServers
volumeServersOverAverage = volume servers with volumeId's ec shard counts > averageShardsPerEcRack
ecShardsToMove = select overflown ec shards from volumeServersOverAverage
for each ecShardsToMove {
destVolumeServer = pickOneVolumeServer(volumeServer~shardCount, volumeServer~volumeIdShardCount, ecShardReplicaPlacement)
pickOneEcNodeAndMoveOneShard(destVolumeServers)
}
}
// move ec shards while keeping shard distribution for the same volume unchanged or more even
func balanceEcRack(rack){
averageShardCount = total shards / numVolumeServers
for hasMovedOneEcShard {
sort all volume servers ordered by the number of local ec shards
pick the volume server A with the lowest number of ec shards x
pick the volume server B with the highest number of ec shards y
if y > averageShardCount and x +1 <= averageShardCount {
if B has a ec shard with volume id v that A does not have {
move one ec shard v from B to A
hasMovedOneEcShard = true
}
}
}
}
`
` + ecBalanceAlgorithmDescription
}
func (c *commandEcBalance) HasTag(CommandTag) bool {