Commit fe181797 authored by Jim Harris's avatar Jim Harris Committed by Tomasz Zawadzki
Browse files

rocksdb: remove the deprecated rocksdb support 



Signed-off-by: default avatarJim Harris <jim.harris@nvidia.com>
Change-Id: Ia3a785de320ec4a2c79ff231f8ee3f397e991ee2
Reviewed-on: https://review.spdk.io/c/spdk/spdk/+/26449


Reviewed-by: default avatarChangpeng Liu <changpeliu@tencent.com>
Tested-by: default avatarSPDK Automated Test System <spdkbot@gmail.com>
Reviewed-by: default avatarKonrad Sztyber <ksztyber@nvidia.com>
Community-CI: Mellanox Build Bot
Reviewed-by: default avatarTomasz Zawadzki <tomasz@tzawadzki.com>
parent 8a8e078f

MAINTAINERS

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@@ -68,7 +68,6 @@ F: app/fio/bdev/ 


BLOB FILESYSTEM

F:	lib/blobfs/

F:	lib/rocksdb/

F:	module/blobfs/

S:	Obsolete

autotest.sh

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@@ -266,7 +266,6 @@ if [ $SPDK_RUN_FUNCTIONAL_TEST -eq 1 ]; then 
	fi



	if [ $SPDK_TEST_BLOBFS -eq 1 ]; then

		run_test "rocksdb" $rootdir/test/blobfs/rocksdb/rocksdb.sh

		run_test "blobstore" $rootdir/test/blobstore/blobstore.sh

		run_test "blobstore_grow" $rootdir/test/blobstore/blobstore_grow/blobstore_grow.sh

		run_test "blobfs" $rootdir/test/blobfs/blobfs.sh

deprecation.md

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@@ -62,9 +62,3 @@ a bdev of the correct size. 
This entire blobfs library is deprecated and will be removed in 25.09 release.

All functions in this library are effectively deprecated, but only these two

are officially marked as such to ensure the library's deprecation is noticed.
 


### rocksdb



The SPDK rocksdb plugin is deprecated and will be removed in 25.09 release.

This C++ plugin exports no public APIs, so none are listed here, but

the pluging will emit deprecation warnings when usage is detected.

doc/Doxyfile

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@@ -809,7 +809,6 @@ INPUT += \ 
                         bdev_module.md \

                         bdev_pg.md \

                         blob.md \

                         blobfs.md \

                         changelog.md \

                         concurrency.md \

                         containers.md \

doc/blobfs.md

deleted100644 → 0
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# BlobFS (Blobstore Filesystem) {#blobfs}



## BlobFS Getting Started Guide {#blobfs_getting_started}



## RocksDB Integration {#blobfs_rocksdb}



Clone and build the SPDK repository as per https://github.com/spdk/spdk



~~~{.sh}

git clone https://github.com/spdk/spdk.git

cd spdk

./configure

make

~~~



Clone the RocksDB repository from the SPDK GitHub fork into a separate directory.

Make sure you check out the `6.15.fb` branch.



~~~{.sh}

cd ..

git clone -b 6.15.fb https://github.com/spdk/rocksdb.git

~~~



Build RocksDB.  Only the `db_bench` benchmarking tool is integrated with BlobFS.



~~~{.sh}

cd rocksdb

make db_bench SPDK_DIR=relative_path/to/spdk

~~~



Or you can also add `DEBUG_LEVEL=0` for a release build (need to turn on `USE_RTTI`).



~~~{.sh}

export USE_RTTI=1 && make db_bench DEBUG_LEVEL=0 SPDK_DIR=relative_path/to/spdk

~~~



Create an NVMe section in the configuration file using SPDK's `gen_nvme.sh` script.



~~~{.sh}

scripts/gen_nvme.sh --json-with-subsystems > /usr/local/etc/spdk/rocksdb.json

~~~



Verify the configuration file has specified the correct NVMe SSD.

If there are any NVMe SSDs you do not wish to use for RocksDB/SPDK testing, remove them from the configuration file.



Make sure you have at least 5GB of memory allocated for huge pages.

By default, the SPDK `setup.sh` script only allocates 2GB.

The following will allocate 5GB of huge page memory (in addition to binding the NVMe devices to uio/vfio).



~~~{.sh}

HUGEMEM=5120 scripts/setup.sh

~~~



Create an empty SPDK blobfs for testing.



~~~{.sh}

test/blobfs/mkfs/mkfs /usr/local/etc/spdk/rocksdb.json Nvme0n1

~~~



At this point, RocksDB is ready for testing with SPDK.  Three `db_bench` parameters are used to configure SPDK:



1. `spdk` - Defines the name of the SPDK configuration file.  If omitted, RocksDB will use the default PosixEnv implementation

   instead of SpdkEnv. (Required)

2. `spdk_bdev` - Defines the name of the SPDK block device which contains the BlobFS to be used for testing. (Required)

3. `spdk_cache_size` - Defines the amount of userspace cache memory used by SPDK.  Specified in terms of megabytes (MB).

   Default is 4096 (4GB).  (Optional)



SPDK has a set of scripts which will run `db_bench` against a variety of workloads and capture performance and profiling

data.  The primary script is `test/blobfs/rocksdb/rocksdb.sh`.



## FUSE



BlobFS provides a FUSE plug-in to mount an SPDK BlobFS as a kernel filesystem for inspection or debug purposes.

The FUSE plug-in requires fuse3 and will be built automatically when fuse3 is detected on the system.



~~~{.sh}

test/blobfs/fuse/fuse /usr/local/etc/spdk/rocksdb.json Nvme0n1 /mnt/fuse

~~~



Note that the FUSE plug-in has some limitations - see the list below.



## Limitations



* BlobFS has primarily been tested with RocksDB so far, so any use cases different from how RocksDB uses a filesystem

  may run into issues.  BlobFS will be tested in a broader range of use cases after this initial release.

* Only a synchronous API is currently supported.  An asynchronous API has been developed but not thoroughly tested

  yet so is not part of the public interface yet.  This will be added in a future release.

* File renames are not atomic.  This will be fixed in a future release.

* BlobFS currently supports only a flat namespace for files with no directory support.  Filenames are currently stored

  as xattrs in each blob.  This means that filename lookup is an O(n) operation.  An SPDK btree implementation is

  underway which will be the underpinning for BlobFS directory support in a future release.

* Writes to a file must always append to the end of the file.  Support for writes to any location within the file

  will be added in a future release.