objectfs

How to build

First, you need to build the version of libs3 included in this repo. To do so: just cd libs3 and make and make install. Then compile the project in code: cd code; make

libs3 differences

The libs3 in the repo is the latest from upstream, but with a patched openssl config so it doesn't use deprecated openssl 3.0 functions.

The latest version in ubuntu repos does not incorporate some upstream changes to the API so we can't really use that easily.

How to run

In project directory, set s3 credentials in s3.config, then run:

./objfs-mount -d <s3_bucket>/<s3_prefix> <local_mount_dir>

The bucket MUST have an item called <prefix>.00000000 (8 zeroes). This file is generated with the mkfs.py script. Call it with python mkfs.py <prefix>, then upload the resulting file to the bucket.

Setup guide with minio

snap install minio
systemctl start minio

Navigate to hostname:9001, then:

• Create a bucket obfs-test
• Make it public (for testing permission's dont matter)
• Generate a secret / access key pair
• Run python3 mkfs.py prefix0
• Upload the resulting file to the bucket
• Put credentials into s3.config
• Run the mount executable as usual
• ./objfs-mount -d obfs-test/prefix0 /mnt/obfs-test

Benchmarking with filebench

To compile filebench:

apt install autoconf bison flex
git clone git@github.com:filebench/filebench.git
cd filebench
libtoolize
aclocal
autoheader
automake --add-missing
autoupdate
autoconf
./configure
make

Executable at ./filebench. The modified workloads are in measure/, to run them use filebench -f measure/workload-webserver.f or whatever workload you choose to run.

things that need to get fixed

multi-threading

data structures should be locked so that we can handle multiple threads - I think that will help perforance

checkpointing

We need to implement checkpointing per the description in the paper and in union-mount.md

garbage collection

write coalescing

see write-coalescing.md

snapshot

Maybe. I think it's more important to get union mount working.

union mount

See union-mount.md

possible things to to

low-level FUSE interface

I'm not sure whether or not we should port this to use the FUSE low-level interface. Note that this would mess up using the CS5600 tests.

testing notes

CS5600 tests

I should commit those to the repo. They run directly against the high-level FUSE methods, single-threaded. It's not a stress test, but it tests a lot of cases of different block sizes for reads and writes.

POSIX conformance

We might be able to use https://github.com/pjd/pjdfstest it runs OK with ext4.

I haven't looked too thoroughly, but I think it's more of a standards conformance test than a stress test, although it still could be useful

xfstests (https://github.com/kdave/xfstests)

This is probably much more comprehensive. It's definitely bigger (125K LOC vs 20K)

It would take a bit of shell scripting to pass object prefixes instead of partition names, but I don't think it would be a huge deal

stress test

Not sure if this would be helpful, or how much work it would be to use it: https://github.com/google/file-system-stress-testing

things we'll fail

hard links - any tests relying on them are going to fail. I think adding *them is fairly trivial - we've got inodes, we just have to add a reference *count to file objects.

fsync/fsyncdir - I don't know if we need to do anything more with them

holes - I'm not sure if we support holes properly, or if we need to.