Allow cluster to start when only n/2 servers are up (#4066)

Fixes #3234.

Relaxes the quorum requirement to start the object layer, and skips
quick-healing at start-up (as no write quorum is present).
master
Aditya Manthramurthy 8 years ago committed by Harshavardhana
parent 6e9ac8db59
commit 604417baf4
  1. 7
      cmd/prepare-storage.go
  2. 10
      cmd/xl-v1.go

@ -132,13 +132,14 @@ func prepForInitXL(firstDisk bool, sErrs []error, diskCount int) InitActions {
}
quorum := diskCount/2 + 1
readQuorum := diskCount / 2
disksOffline := errMap[errDiskNotFound]
disksFormatted := errMap[nil]
disksUnformatted := errMap[errUnformattedDisk]
disksCorrupted := errMap[errCorruptedFormat]
// No Quorum lots of offline disks, wait for quorum.
if disksOffline >= quorum {
if disksOffline > readQuorum {
return WaitForQuorum
}
@ -168,7 +169,7 @@ func prepForInitXL(firstDisk bool, sErrs []error, diskCount int) InitActions {
}
// Already formatted and in quorum, proceed to initialization of object layer.
if disksFormatted >= quorum {
if disksFormatted >= readQuorum {
if disksFormatted+disksOffline == diskCount {
return InitObjectLayer
}
@ -293,7 +294,7 @@ func initStorageDisks(endpoints []*url.URL) ([]StorageAPI, error) {
return storageDisks, nil
}
// Format disks before initialization object layer.
// Format disks before initialization of object layer.
func waitForFormatXLDisks(firstDisk bool, endpoints []*url.URL, storageDisks []StorageAPI) (formattedDisks []StorageAPI, err error) {
if len(endpoints) == 0 {
return nil, errInvalidArgument

@ -155,6 +155,16 @@ func newXLObjects(storageDisks []StorageAPI) (ObjectLayer, error) {
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)
}

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