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.
- 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
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.
Removes the bloom filter since it has so limited usability, often gets saturated anyway and adds a bunch of complexity to the scanner.
Also removes a tiny bit of CPU by each write operation.
xl.meta gets written and never rolled back, however
we definitely need to validate the state that is
persisted on the disk, if there are inconsistencies
- more than write quorum we should return an error
to the client
- if write quorum was achieved however there are
inconsistent xl.meta's we should simply trigger
an MRF on them
The path is marked dirty automatically when healObject() is called, which is
wrong. HealObject() is called during self-healing and this will lead to
an increase in the false positive result of the bloom filter.
Also move NSUpdated() from renameData() and call it directly in
CompleteMultipart and PutObject, this is not a functional change but
it will make it less prone to errors in the future.
`mc admin heal -r <alias>` in a multi setup pools returns incorrectly
grey objects. The reason is that erasure-server-pools.HealObject() runs
HealObject in all pools and returns the result of the first nil
error. However, in the lower erasureObject level, HealObject() returns
nil if an object does not exist + missing error in each disk of the object
in that pool, therefore confusing mc.
Make erasureObject.HealObject() to return not found error in the lower
level, so at least erasureServerPools will know what pools to ignore.
this PR also fixes a situation where incorrect
partsMetadata slice was used where fi.Data was
re-used from a single drive causing duplication
of the shards across all drives.
This happens for situations where shouldHeal()
returns true for all drives > parityBlocks.
To avoid this we should never attempt to heal on all
drives > parityBlocks, unless we are doing metadata
migration from xl.json -> xl.meta
When scanning using normal mode, HealObject() can report an
error saying that it found a corrupted part. This doesn't have
when HealObject() is called with bitrot scan flag. However, when
this happens, we can still restart HealObject() with the bitrot scan.
This is also important because this means the scanner and the
new disks healer will not be able to heal an object that doesn't
exist in a specific disk and has corruption in another disk.
Also without this PR, mc admin heal command without bitrot will report
an error.
Deleting bulk objects had an issue since the relevant versionID
is not passed through the layers to ensure that the dangling
object purge actually works cleanly.
This is a continuation of quorum related error returned by
multi-object delete API from #14248
This PR ensures that we pass down correct information as
well as extend the scope of dangling object detection.
This PR simplifies few things
- Multipart parts are renamed, upon failure are unrenamed() keep this
multipart specific behavior it is needed and works fine.
- AbortMultipart should blindly delete once lock is acquired instead
of re-reading metadata and calculating quorum, abort is a delete()
operation and client has no business looking for errors on this.
- Skip Access() calls to folders that are operating on
`.minio.sys/multipart` folder as well.
Large clusters with multiple sets, or multi-pool setups at times might
fail and report unexpected "file not found" errors. This can become
a problem during startup sequence when some files need to be created
at multiple locations.
- This PR ensures that we nil the erasure writers such that they
are skipped in RenameData() call.
- RenameData() doesn't need to "Access()" calls for `.minio.sys`
folders they always exist.
- Make sure PutObject() never returns ObjectNotFound{} for any
errors, make sure it always returns "WriteQuorum" when renameData()
fails with ObjectNotFound{}. Return appropriate errors for all
other cases.
In a multi-pool setup when disks are coming up, or in a single pool
setup let's say with 100's of erasure sets with a slow network.
It's possible when healing is attempted on `.minio.sys/config`
folder, it can lead to healing unexpectedly deleting some policy
files as dangling due to a mistake in understanding when `isObjectDangling`
is considered to be 'true'.
This issue happened in commit 30135eed86
when we assumed the validMeta with empty ErasureInfo is considered
to be fully dangling. This implementation issue gets exposed when
the server is starting up.
This is most easily seen with multiple-pool setups because of the
disconnected fashion pools that come up. The decision to purge the
object as dangling is taken incorrectly prior to the correct state
being achieved on each pool, when the corresponding drive let's say
returns 'errDiskNotFound', a 'delete' is triggered. At this point,
the 'drive' comes online because this is part of the startup sequence
as drives can come online lazily.
This kind of situation exists because we allow (totalDisks/2) number
of drives to be online when the server is being restarted.
Implementation made an incorrect assumption here leading to policies
getting deleted.
Added tests to capture the implementation requirements.
The current usage of assuming `default` parity of `4` is not correct
for all objects stored on MinIO, objects in .minio.sys have maximum
parity, healing won't trigger on these objects due to incorrect
verification of quorum.
Harshavardhana
Aditya Manthramurthy
Kaan Kabalak
Anis Eleuch
Praveen raj Mani
Krishnan Parthasarathi
ferhat elmas
Klaus Post
Poorna
ebozduman