daviesliu
Joined 13 years ago
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215
Submissions
110
Member since
Jan 2
Recent submissions
Comment · 9 months ago
JuiceFS can be scaled to hundreds of PB by design, also is verified by thousands of users in production [1].
[1] https://juicefs.com/en/blog/company/2025-recap-artificial-in...
Comment · 1 year ago
Founder of JuiceFS here, congrats to the Launch! I'm super excited to see more people doing creative things in the using-S3-as-file-system space. When we started JuiceFS back in 2017, applied YC for 2 times but no luck.
We are still working hard on it, hoping that we can help people with different workloads with different tech!
Comment · 2 years ago
This post said another topic: how to backup the metadata of JuiceFS in readable format (JSON) and restore it into an empty database.
Comment · 2 years ago
The recover process is similar to what a database does after a crash, it loads the recent snapshot in disk and apply any newer transaction logs.
Comment · 2 years ago
The S3 API allow user to specify the hash of content as HTTP header, it will be verified by the JuiceFS gateway and persisted into JuiceFS as ETag.
With POSIX API or HDFS, there is no such API to do that, unfortunately.
Comment · 2 years ago
JuiceFS relies on the object store to provide integrity for data. Besides that, JuiceFS stores the checksum of each object as tags in S3, and verifies that when downloading the objects.
Inside the metadata service, it uses merkle tree (hash of hash) to verify the integrity of whole namespace (including id of data blocks) between RAFT replicas. Once we store the hash (4 bytes) of each objects into metadata, it should provide the integrity of the whole namespace.
Comment · 2 years ago
The company may want the product to be difficult to use, so they can sell more support, that's not win-win for both sides.
Comment · 2 years ago
Agreed, the all-in-one solution (Ceph) should be better, if you have to setup all the components.
If you already have the infra (databases and object stores), then JuiceFS is the easiest solution to have a distributed file system.
Comment · 2 years ago
JuiceFS is similar to HDFS/CephFS/Lustre, so it MUST has a component to manage metadata, similar to NameNode of HDFS or MDS of CephFS, this point of failure is the problem we have to address.
The underlying blob store systems is similar to DataNode or OSD in other distributed file system, could be slower than them a little bit because of the middle layers, the overall performance is determined by the disks.
So we can expect similar performance comparing to HDFS/CephFS, the benchmark results also confirm that.
Comment · 3 years ago
If you really expect a file system experience over GCS, please try JuiceFS [1], which scales to 10 billions of files pretty well with TiKV or FoundationDB as meta engine.
PS, I'm founder of JuiceFS.
Comment · 3 years ago
Usually the meta engine or object storage can scale horizontally by itself, JuiceFS is middleware to talk to these two services.
To serve S3 request, you can setup multiple S3 gateway and put a load director in front of them.
Comment · 3 years ago
Agreed, it's very hard, that's why GFS and HDFS had give up some parts of POSIX compatibility.
Per CAP, it's addressed by different meta engines (CP system, Redis, MySQL, TiKV) and also different object stores (AP system). When the meta engine is not available, the operation to JuiceFS will be blocked for a while and finally it returns EIO. When object store returns 404 (object not found), which means it's not consistent with the meta engine, it will be retried for a while, may return EIO if it's not recovered.
The file format is carefully designed to workaround the consistency issue from object store and local cache. Any part of data is written into object store and local cache with unique ID, so you will not go stale data once the metadata is correct [1].
Within a mount point, JuiceFS provides read-after-write consistency. Across clusters, JuiceFS provides open-after-close consistency, which should be enough for most of the applications, also provide good balance between consistency and performance.
[1] https://juicefs.com/docs/community/architecture/#how-juicefs...
Comment · 3 years ago
Atomic file/directory renames/moves is the fundamental feature of JuiceFS, which makes it truely a file system rather than a proxy to S3, please check the docs for all the compatibility details [1].
Founder and CEO at Juicedata, Inc.
[email protected]