Hey, I have another more general question: do you have some recommendation for the most performant way to upload objects? Right now I am looping through the desired files and it's estimating COCO 2017 val set (with 5000 images, 5000 small JSON) to take 3 hours to upload

HI @Conor Simmons - Have you considered importing instead of uploading?

Yes I've considered it. But I was under the impression that you can't really do version control with just importing. See this thread: https://lakefs.slack.com/archives/C02CV7MUV4G/p1674842235272179?thread_ts=1674838530.053799&cid=C02CV7MUV4G

You can version control with an import (that’s actually the most common use). It is just that in your case, if I understand correctly, you want to later on make the changes directly on the object store (not through lakeFS) you imported form, and import again. Correct? I’m assuming that whatever writes to the object store can’t work directly against lakeFS after importing the data? i.e. import the data as a once time thing, and then work with the S3 gateway, as opposed to cloning over and over again?

I’m assuming that whatever writes to the object store can’t work directly against lakeFS after importing the data?

I'm not sure what you mean by this

Usually, once you imported the data, you would work directly against lakeFS for version control. As opposed to making modifications directly on S3 without lakeFS and then reuploading / cloning / importing.

I guess I'm confused by this phrase

work directly against lakeFS

Does this mean work with LakeFS? Or against meaning some other tool?

Sure!

Doesn't this demo use

client.objects.upload_object

which is an upload not an import?

It does. But it will work just the same (with the gateway) for an import

So I shouldn't need pyspark then?

(not to partition images, but tou can work with them the same as you would directly with the object store - via lakefs)

Ah I think I found the better docs page: https://docs.lakefs.io/integrations/spark.html#use-the-s3-gateway

Specifically Spark can work either with the gateway or via the lakeFS hadoop File system client (like the page you indicated).

So Spark is inherently part of using the gateway, correct?

You can work with spark either with the gateway or with the lakeFS hadoop filesystem client

I'm wondering whether or not I need to use Spark

You don’t have to use spark to benefit from lakeFS

Were you originally suggesting to use Spark? (here)

Let me try and put it some other way (from the origin of the conversation as I understand it) When working with big data, you typically want the data to stay in place. When writing code, it is common to “check out” a local version of the code to your desktop and work against a copy of the code. However, when working with big data, it is unreasonable to copy terabytes (or more) of files locally to experiment, develop, test or transform the data. Working with lakeFS, the data stays in place and the branch isolation is achieved via pointers manipulations (https://docs.lakefs.io/understand/model.html#objects), pointing to the data staying on the object store. Meaning, you won’t check out a local copy of the data, but rather create a separate branch and work against that branch. Once done, if you want to “push” the changes back, merge back your isolated branch.

whatever accesses the data, will do so, via lakeFS and not directly to the object store

got it, I am doing that already. But with upload

Yes. Just import

and then mofidy the files via lakeFS

What do you mean by modify in terms of CLI commands or Python SDK usage?

How do you work with your object store today? What changes the files there?

I would say

lakectl fs upload

to add or modify and

lakectl fs rm

to remove

You are not misunderstanding the use case. I think we might be misaligned on the implementation 🙂

You can easily access a historical commit in lakeFS and get the full data set as it was at the time of that commit.

Got it. I've done it with upload but if there's a more efficient way I'd love to try it.

What creates the files initially on the object store?

So, the files are being created locally. Previously, before importing, I've synced them to S3 with

b2 sync

(BackBlaze)

If you import once and them use lakectl to upload / delete as you all out that will be available. That might be better in cases where the entire data set doesn’t change on every run

I also have rclone in my tool set so maybe it's better to think using that. You're then suggesting 1. when initially creating the dataset,

rclone sync

to S3 store. Say there's 100,000 images 2. import to LakeFS 3. When adding, deleting, or modifying to the dataset, use

lakectl fs upload

or

lakectl fs rm

I might be missing something - but I would say assuming the files are already on S3, you can just import as opposed to rclone (which will copy the files). I’ll sync with @Ariel Shaqed (Scolnicov) & @Elad Lachmi tomorrow to get the full context of the conversation

(For rclone I meant using it independent of lakefs, so rclone from local storage to object store. Same functionality as

b2 sync

)

Ok.

Ok I will try it. I was under the impression that with the 100,000 images I originally imported, if I modify them, I won't be able to go back to their original version. Maybe if I never modify them again in the S3 store directly?

Exactly - modify them via lakeFS (for example, with the lakectl command)

Got it. What if I want to modify all 100,000? Would a re-import make sense? Or should I never import again?

This goes back to your original question - if you are planning to delete files from the original import, you will loose the ability to go back to them. Since an import only creates pointers to the files.

Ok I think I'm following then. But why should I import in the first place? To be quicker than upload?

Quicker and you don’t actually create a copy of the files.

I thought upload could also be zero-copy

Upload physically uploads a file. You can branch later on and that will be a zero-copy operation. But the initial upload adds a file to the object storage.

But by the object storage you just mean the S3 store right? Don't I need to do the same with import?

I understand you use rclone to bring the data to an objet store unrelated to lakeFS. What I mean is when you upload, the file will be placed on the object store in which the lakeFS repository sits. When you import, we will only create a pointed to the file, in it’s original place.

an objet store unrelated to lakeFS.

the object store in which the lakeFS repository sits.

what if this is the same object store?

I would suggest reading more here: https://lakefs.io/blog/best-practices-to-adopt-lakefs/

I think I'm on the same understanding of import and upload... But my confusion is still on why upload is slower than rclone+import? It seems more user friendly to just stick with uploading everything

I’ll sync with Ariel and Elad tomorrow to understand that part better.

Ok - thanks for your help and have a good night!

Yeah, sounds about right, but that's the raw transfer Where you might see a difference is in the req/res overhead and processing

Hi @Conor Simmons, One issue with the s3 gateway is, as you've noticed, that all data flows through lakeFS. That's because of the s3 protocol... There's no way around it with that protocol. You might see better performance with what I like to call a "direct" upload, using the lakeFS API. To do that you'd copy your file over on s3 to some new name (typically that name will be a uuid), then call an appropriate lakeFS API that links an existing object on the s3 backing store to wherever you want on your lakeFS branch. This will work! How much speedup you'll see will depend on how much faster you can perform the copies on s3 than on the lakeFS s3 gateway. For huge numbers of files, you can probably parallelize this and win big... Especially if it's also a lot of data to copy. However now you're managing the data objects yourself. That means lakeFS won't manage them. So for instance you'll not be able to get any garbage collection from lakeFS, because we cannot safely delete what we do not control. I suspect there might be a feature request hiding in here somewhere, about importing and copying the backing store. Justifying it would probably need a lot of numbers.

Thanks, I appreciate all the input. I will take a look into some of these options

Sorry about the number of options. It really is quite subtle, and each of the methods has unique advantages. I wish I could just tell you "this is the best way", but it really depends on so many parameters.