```
mc admin config set alias/ storage_class standard=EC:3
```
should only succeed if parity ratio is valid for all
server pools, if not we should fail proactively.
This PR also needs to bring other changes now that
we need to cater for variadic drive counts per pool.
Bonus fixes also various bugs reproduced with
- GetObjectWithPartNumber()
- CopyObjectPartWithOffsets()
- CopyObjectWithMetadata()
- PutObjectPart,PutObject with truncated streams
Use separate sync.Pool for writes/reads
Avoid passing buffers for io.CopyBuffer()
if the writer or reader implement io.WriteTo or io.ReadFrom
respectively then its useless for sync.Pool to allocate
buffers on its own since that will be completely ignored
by the io.CopyBuffer Go implementation.
Improve this wherever we see this to be optimal.
This allows us to be more efficient on memory usage.
```
385 // copyBuffer is the actual implementation of Copy and CopyBuffer.
386 // if buf is nil, one is allocated.
387 func copyBuffer(dst Writer, src Reader, buf []byte) (written int64, err error) {
388 // If the reader has a WriteTo method, use it to do the copy.
389 // Avoids an allocation and a copy.
390 if wt, ok := src.(WriterTo); ok {
391 return wt.WriteTo(dst)
392 }
393 // Similarly, if the writer has a ReadFrom method, use it to do the copy.
394 if rt, ok := dst.(ReaderFrom); ok {
395 return rt.ReadFrom(src)
396 }
```
From readahead package
```
// WriteTo writes data to w until there's no more data to write or when an error occurs.
// The return value n is the number of bytes written.
// Any error encountered during the write is also returned.
func (a *reader) WriteTo(w io.Writer) (n int64, err error) {
if a.err != nil {
return 0, a.err
}
n = 0
for {
err = a.fill()
if err != nil {
return n, err
}
n2, err := w.Write(a.cur.buffer())
a.cur.inc(n2)
n += int64(n2)
if err != nil {
return n, err
}
```
Add `MINIO_API_EXTEND_LIST_CACHE_LIFE` that will extend
the life of generated caches for a while.
This changes caches to remain valid until no updates have been
received for the specified time plus a fixed margin.
This also changes the caches from being invalidated when the *first*
set finishes until the *last* set has finished plus the specified time
has passed.
configurable remote transport timeouts for some special cases
where this value needs to be bumped to a higher value when
transferring large data between federated instances.
