minio/cmd/storage-interface.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

97 lines
2.8 KiB
Go

/*
* Minio Cloud Storage, (C) 2016 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 (
"io"
"github.com/minio/minio/pkg/disk"
)
// StorageAPI interface.
type StorageAPI interface {
// Stringified version of disk.
String() string
// Storage operations.
IsOnline() bool // Returns true if disk is online.
Close() error
DiskInfo() (info disk.Info, err error)
// Volume operations.
MakeVol(volume string) (err error)
ListVols() (vols []VolInfo, err error)
StatVol(volume string) (vol VolInfo, err error)
DeleteVol(volume string) (err error)
// File operations.
ListDir(volume, dirPath string) ([]string, error)
ReadFile(volume string, path string, offset int64, buf []byte, verifier *BitrotVerifier) (n int64, err error)
PrepareFile(volume string, path string, len int64) (err error)
AppendFile(volume string, path string, buf []byte) (err error)
RenameFile(srcVolume, srcPath, dstVolume, dstPath string) error
StatFile(volume string, path string) (file FileInfo, err error)
DeleteFile(volume string, path string) (err error)
// Read all.
ReadAll(volume string, path string) (buf []byte, err error)
}
// storageReader is an io.Reader view of a disk
type storageReader struct {
storage StorageAPI
volume, path string
offset int64
}
func (r *storageReader) Read(p []byte) (n int, err error) {
nn, err := r.storage.ReadFile(r.volume, r.path, r.offset, p, nil)
r.offset += nn
n = int(nn)
if err == io.ErrUnexpectedEOF && nn > 0 {
err = io.EOF
}
return
}
// storageWriter is a io.Writer view of a disk.
type storageWriter struct {
storage StorageAPI
volume, path string
}
func (w *storageWriter) Write(p []byte) (n int, err error) {
err = w.storage.AppendFile(w.volume, w.path, p)
if err == nil {
n = len(p)
}
return
}
// StorageWriter returns a new io.Writer which appends data to the file
// at the given disk, volume and path.
func StorageWriter(storage StorageAPI, volume, path string) io.Writer {
return &storageWriter{storage, volume, path}
}
// StorageReader returns a new io.Reader which reads data to the file
// at the given disk, volume, path and offset.
func StorageReader(storage StorageAPI, volume, path string, offset int64) io.Reader {
return &storageReader{storage, volume, path, offset}
}