Currently if the object does not exist in quorum disks of an erasure
set, the dangling code is never called because the returned error will
be errFileNotFound or errFileVersionNotFound;
With this commit, when errFileNotFound or errFileVersionNotFound is
returning when trying to calculate the quorum of a given object, the
code checks if a disk returned nil, which means a stale object exists in
that disk, that will trigger deleteIfDangling() function
if erasure upgrade is needed rely on the in-memory
values, instead of performing a "DiskInfo()" call.
https://brendangregg.com/blog/2016-09-03/sudden-disk-busy.html
for HDDs these are problematic, lets avoid this because
there is no value in "being" absolutely strict here
in terms of parity. We are okay to increase parity
as we see based on the in-memory online/offline ratio.
without this the rename2() can rename the previous dataDir
causing issues for different versions of the object, only
latest version is preserved due to this bug.
Added healing code to ensure recovery of such content.
Errors such as
```
returned an error (context deadline exceeded) (*fmt.wrapError)
```
```
(msgp: too few bytes left to read object) (*fmt.wrapError)
```
objects with 10,000 parts and many of them can
cause a large memory spike which can potentially
lead to OOM due to lack of GC.
with previous PR reducing the memory usage significantly
in #17963, this PR reduces this further by 80% under
repeated calls.
Scanner sub-system has no use for the slice of Parts(),
it is better left empty.
```
benchmark old ns/op new ns/op delta
BenchmarkToFileInfo/ToFileInfo-8 295658 188143 -36.36%
benchmark old allocs new allocs delta
BenchmarkToFileInfo/ToFileInfo-8 61 60 -1.64%
benchmark old bytes new bytes delta
BenchmarkToFileInfo/ToFileInfo-8 1097210 227255 -79.29%
```
- this PR avoids sending a large ChecksumInfo slice
when its not needed
- also for a file with XLV2 format there is no reason
to allocate Checksum slice while reading
.metacache objects are transient in nature, and are better left to
use page-cache effectively to avoid using more IOPs on the disks.
this allows for incoming calls to be not taxed heavily due to
multiple large batch listings.
Bonus:
- avoid calling DiskInfo() calls when missing blocks
instead heal the object using MRF operation.
- change the max_sleep to 250ms beyond that we will
not stop healing.
on unversioned buckets its possible that 0-byte objects
might lose quorum on flaky systems, allow them to be same
as DELETE markers. Since practically speak they have no
content.
Optimize DeleteObject API to avoid extra
GetObjectInfo call on the replicating side.
For receiving side, it is just a regular
DeleteObject call.
Bonus: Fix a corner case where version purged is
absent on target (either due to replication not yet
complete or target version already deleted in a
one-way replication or when replication was disabled).
In such cases, mark version purge complete.
* Reduce allocations
* Add stringsHasPrefixFold which can compare string prefixes, while ignoring case and not allocating.
* Reuse all msgp.Readers
* Reuse metadata buffers when not reading data.
* Make type safe. Make buffer 4K instead of 8.
* Unslice
there is a possibility that slow drives can actually add latency
to the overall call, leading to a large spike in latency.
this can happen if there are other parallel listObjects()
calls to the same drive, in-turn causing each other to sort
of serialize.
this potentially improves performance and makes PutObject()
also non-blocking.
on "unversioned" buckets there are situations
when successive concurrent I/O can lead to
an inconsistent state() with mtime while the
etag might be the same for the object on disk.
in such a scenario it is possible for us to
allow reading of the object since etag matches
and if etag matches we are guaranteed that we
have enough copies the object will be readable
and same.
This PR allows fallback in such scenarios.
fixes an issue under bucket replication could cause
ETags for replicated SSE-S3 single part PUT objects,
to fail as we would attempt a decryption while listing,
or stat() operation.
Anis Eleuch
Harshavardhana
Aditya Manthramurthy
Poorna
jiuker
Kaan Kabalak
Klaus Post
Krishnan Parthasarathi
Praveen raj Mani
ferhat elmas