[Gluster-Maintainers] [Gluster-users] Proposal to mark few features as Deprecated / SunSet from Version 5.0

Tue Mar 19 12:09:01 UTC 2019

Hi,

Looking into something else I fell over this proposal. Being a shop that
are going into "Leaving GlusterFS" mode, I thought I would give my two
cents.

While being partially an HPC shop with a few Lustre filesystems,  we
chose GlusterFS for an archiving solution (2-3 PB), because we could
find files in the underlying ZFS filesystems if GlusterFS went sour.

We have used the access to the underlying files plenty, because of the
continuous instability of GlusterFS'. Meanwhile, Lustre have been almost
effortless to run and mainly for that reason we are planning to move
away from GlusterFS.

Reading this proposal kind of underlined that "Leaving GluserFS" is the
right thing to do. While I never understood why GlusterFS has been in
feature crazy mode instead of stabilizing mode, taking away crucial
features I don't get. With RoCE, RDMA is getting mainstream. Quotas are
very useful, even though the current implementation are not perfect.
Tiering also makes so much sense, but, for large files, not on a
per-file level.

To be honest we only use quotas. We got scared of trying out new
performance features that potentially would open up a new back of issues.

Sorry for being such a buzzkill. I really wanted it to be different.

Cheers,
Hans Henrik

On 19/07/2018 08.56, Amar Tumballi wrote:
> *
>
> Hi all,
>
> Over last 12 years of Gluster, we have developed many features, and
> continue to support most of it till now. But along the way, we have
> figured out better methods of doing things. Also we are not actively
> maintaining some of these features.
>
> We are now thinking of cleaning up some of these ‘unsupported’
> features, and mark them as ‘SunSet’ (i.e., would be totally taken out
> of codebase in following releases) in next upcoming release, v5.0. The
> release notes will provide options for smoothly migrating to the
> supported configurations.
>
> If you are using any of these features, do let us know, so that we can
> help you with ‘migration’.. Also, we are happy to guide new developers
> to work on those components which are not actively being maintained by
> current set of developers.
>
>
>       List of features hitting sunset:
>
>
>         ‘cluster/stripe’ translator:
>
> This translator was developed very early in the evolution of
> GlusterFS, and addressed one of the very common question of
> Distributed FS, which is “What happens if one of my file is bigger
> than the available brick. Say, I have 2 TB hard drive, exported in
> glusterfs, my file is 3 TB”. While it solved the purpose, it was very
> hard to handle failure scenarios, and give a real good experience to
> our users with this feature. Over the time, Gluster solved the problem
> with it’s ‘Shard’ feature, which solves the problem in much better
> way, and provides much better solution with existing well supported
> stack. Hence the proposal for Deprecation.
>
> If you are using this feature, then do write to us, as it needs a
> proper migration from existing volume to a new full supported volume
> type before you upgrade.
>
>
>         ‘storage/bd’ translator:
>
> This feature got into the code base 5 years back with this patch
> <http://review.gluster.org/4809>[1]. Plan was to use a block device
> directly as a brick, which would help to handle disk-image storage
> much easily in glusterfs.
>
> As the feature is not getting more contribution, and we are not seeing
> any user traction on this, would like to propose for Deprecation.
>
> If you are using the feature, plan to move to a supported gluster
> volume configuration, and have your setup ‘supported’ before upgrading
> to your new gluster version.
>
>
>         ‘RDMA’ transport support:
>
> Gluster started supporting RDMA while ib-verbs was still new, and very
> high-end infra around that time were using Infiniband. Engineers did
> work with Mellanox, and got the technology into GlusterFS for better
> data migration, data copy. While current day kernels support very good
> speed with IPoIB module itself, and there are no more bandwidth for
> experts in these area to maintain the feature, we recommend migrating
> over to TCP (IP based) network for your volume.
>
> If you are successfully using RDMA transport, do get in touch with us
> to prioritize the migration plan for your volume. Plan is to work on
> this after the release, so by version 6.0, we will have a cleaner
> transport code, which just needs to support one type.
>
>
>         ‘Tiering’ feature
>
> Gluster’s tiering feature which was planned to be providing an option
> to keep your ‘hot’ data in different location than your cold data, so
> one can get better performance. While we saw some users for the
> feature, it needs much more attention to be completely bug free. At
> the time, we are not having any active maintainers for the feature,
> and hence suggesting to take it out of the ‘supported’ tag.
>
> If you are willing to take it up, and maintain it, do let us know, and
> we are happy to assist you.
>
> If you are already using tiering feature, before upgrading, make sure
> to do gluster volume tier detachall the bricks before upgrading to
> next release. Also, we recommend you to use features like dmcacheon
> your LVM setup to get best performance from bricks.
>
>
>         ‘Quota’
>
> This is a call out for ‘Quota’ feature, to let you all know that it
> will be ‘no new development’ state. While this feature is ‘actively’
> in use by many people, the challenges we have in accounting mechanisms
> involved, has made it hard to achieve good performance with the
> feature. Also, the amount of extended attribute get/set operations
> while using the feature is not very ideal. Hence we recommend our
> users to move towards setting quota on backend bricks directly (ie,
> XFS project quota), or to use different volumes for different
> directories etc.
>
> As the feature wouldn’t be deprecated immediately, the feature doesn’t
> need a migration plan when you upgrade to newer version, but if you
> are a new user, we wouldn’t recommend setting quota feature. By the
> release dates, we will be publishing our best alternatives guide for
> gluster’s current quota feature.
>
> Note that if you want to contribute to the feature, we have project
> quota based issue open
> <https://github.com/gluster/glusterfs/issues/184>[2] Happy to get
> contributions, and help in getting a newer approach to Quota.
>
>
> ------------------------------------------------------------------------
>
> These are our set of initial features which we propose to take out of
> ‘fully’ supported features. While we are in the process of making the
> user/developer experience of the project much better with providing
> well maintained codebase, we may come up with few more set of features
> which we may possibly consider to move out of support, and hence keep
> watching this space.
>
> [1] - http://review.gluster.org/4809
>
> [2] - https://github.com/gluster/glusterfs/issues/184
>
> Regards,
>
> Vijay, Shyam, Amar
>
> *
>
>
>
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