minio/cmd/xl-v1-common.go
Harshavardhana fb96779a8a Add large bucket support for erasure coded backend (#5160)
This PR implements an object layer which
combines input erasure sets of XL layers
into a unified namespace.

This object layer extends the existing
erasure coded implementation, it is assumed
in this design that providing > 16 disks is
a static configuration as well i.e if you started
the setup with 32 disks with 4 sets 8 disks per
pack then you would need to provide 4 sets always.

Some design details and restrictions:

- Objects are distributed using consistent ordering
  to a unique erasure coded layer.
- Each pack has its own dsync so locks are synchronized
  properly at pack (erasure layer).
- Each pack still has a maximum of 16 disks
  requirement, you can start with multiple
  such sets statically.
- Static sets set of disks and cannot be
  changed, there is no elastic expansion allowed.
- Static sets set of disks and cannot be
  changed, there is no elastic removal allowed.
- ListObjects() across sets can be noticeably
  slower since List happens on all servers,
  and is merged at this sets layer.

Fixes #5465
Fixes #5464
Fixes #5461
Fixes #5460
Fixes #5459
Fixes #5458
Fixes #5460
Fixes #5488
Fixes #5489
Fixes #5497
Fixes #5496
2018-02-15 17:45:57 -08:00

86 lines
2.7 KiB
Go

/*
* Minio Cloud Storage, (C) 2016, 2017 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 (
"path"
"github.com/minio/minio/pkg/errors"
)
// getLoadBalancedDisks - fetches load balanced (sufficiently randomized) disk slice.
func (xl xlObjects) getLoadBalancedDisks() (disks []StorageAPI) {
// Based on the random shuffling return back randomized disks.
for _, i := range hashOrder(UTCNow().String(), len(xl.getDisks())) {
disks = append(disks, xl.getDisks()[i-1])
}
return disks
}
// This function does the following check, suppose
// object is "a/b/c/d", stat makes sure that objects ""a/b/c""
// "a/b" and "a" do not exist.
func (xl xlObjects) parentDirIsObject(bucket, parent string) bool {
var isParentDirObject func(string) bool
isParentDirObject = func(p string) bool {
if p == "." || p == "/" {
return false
}
if xl.isObject(bucket, p) {
// If there is already a file at prefix "p", return true.
return true
}
// Check if there is a file as one of the parent paths.
return isParentDirObject(path.Dir(p))
}
return isParentDirObject(parent)
}
// isObject - returns `true` if the prefix is an object i.e if
// `xl.json` exists at the leaf, false otherwise.
func (xl xlObjects) isObject(bucket, prefix string) (ok bool) {
for _, disk := range xl.getLoadBalancedDisks() {
if disk == nil {
continue
}
// Check if 'prefix' is an object on this 'disk', else continue the check the next disk
_, err := disk.StatFile(bucket, path.Join(prefix, xlMetaJSONFile))
if err == nil {
return true
}
// Ignore for file not found, disk not found or faulty disk.
if errors.IsErrIgnored(err, xlTreeWalkIgnoredErrs...) {
continue
}
errorIf(err, "Unable to stat a file %s/%s/%s", bucket, prefix, xlMetaJSONFile)
} // Exhausted all disks - return false.
return false
}
// Calculate the space occupied by an object in a single disk
func (xl xlObjects) sizeOnDisk(fileSize int64, blockSize int64, dataBlocks int) int64 {
numBlocks := fileSize / blockSize
chunkSize := getChunkSize(blockSize, dataBlocks)
sizeInDisk := numBlocks * chunkSize
remaining := fileSize % blockSize
if remaining > 0 {
sizeInDisk += getChunkSize(remaining, dataBlocks)
}
return sizeInDisk
}