nullfuse

nullfuse is a dummy Fuse based filesystem, which allows to measure the performance overhead imposed on Fuse based filesystems.

Building and installation

nullfuse needs the following dependencies to be build:

cmake >= 3.0.0
Fuse >= 2.9

To build and install nullfuse simply follow these steps:

mkdir _build && cd _build
cmake ..
make

Usage

nullfuse can be mounted by running the nullfuse binary with provided mount point, e.g. You can find it in build directory

nullfuse /mnt/nullfuse

To unmount the filesystem use:

fusermount -uz /mnt/nullfuse

All created files and directories, along with their metadata, are persisted in memory until the nullfuse is unmounted. All data written to files in that filesystem however is lost, i.e. they act as /dev/null device. When reading the files which have non-zero size, the reading process will receive a sequence of x characters. e.g.

echo TEST > /mnt/nullfuse/file.txt
cat /mnt/nullfuse/file.txt
xxxx

Testing

Below are some examples of what can be tested with the nullfuse filesystem:

Measure performance of directory creation

time mkdir -p {00..99}/{00..99}         
mkdir -p {00..99}/{00..99}  0,01s user 0,12s system 99% cpu 0,129 total

Measure performance of file creation

time touch {00..99}/{00..99}/file.txt    
touch {00..99}/{00..99}/file.txt  0,00s user 0,09s system 93% cpu 0,105 total

Measure write throughput

dd if=/dev/zero of=file.txt bs=1M count=1000
1000+0 records in
1000+0 records out
1048576000 bytes (1,0 GB, 1000 MiB) copied, 0,577779 s, 1,8 GB/s

Measure read throughput

dd if=file.txt of=/dev/null bs=1M
1000+0 records in
1000+0 records out
1048576000 bytes (1,0 GB, 1000 MiB) copied, 0,128954 s, 8,1 GB/s

Implementation

Most of nullfuse is implemented using C++14 standard except for interfacing with Fuse which is in plain C.

LICENSE

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.

kz2d/nullfuse