Re: Running out of inodes on an NFS which stores repos

From: Kousik Sanagavarapu <five231003@gmail.com>
Date: Sep 8, 2025, 07:05 UTC
Message-ID: <DCN87S14V9G8.3BAV5XX1BDHKM@gmail.com>
In-Reply-To: <aLxUkTzuVaZrWDs2@fruit.crustytoothpaste.net>

On Sat Sep 6, 2025 at 9:04 PM IST, brian m. carlson wrote:

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> On 2025-09-06 at 14:16:12, Kousik Sanagavarapu wrote:
>> Hello everyone,
>
> Hi,
>
>> These git repos come from another service and there are typically
>> thousands of them each day. It is important to note that we only store
>> the .git dir and expose a url which is configured as the remote by
>> default to read and write into this repo.
>>
>> All of these are small repos; usually not many files and not many
>> commits too - I'd say ~5 commits on average.
>>
>> Historically, when we ran out of inodes, we had implemented a few
>> strategies where we used to repack the objects or archive the older
>> repos and move them into another store and bring them back into this
>> NFS and unarchive the repo.
>>
>> However, none of these totally mitigated the issue and we still run
>> into issue as the traffic increases. As a last resort,  we increased
>> the disk size even though there was ton of free space left - just
>> for increasing the number of inodes.
>>
>> We can't delete any of these repos, no matter how old, because they are
>> valuable data.
>>
>> I was wondering if there was some other strategy that we could implement
>> here as this seems like a problem that people might often run into. It
>> would really help to here your thoughts or if you could point me to
>> anywhere else.
>
> There are a couple things that come to mind here.  You can try to set
> `fetch.unpackLimit` to 1, which will cause of the objects pushed into
> the repository to end up in a pack.  That means you'll usually have
> only two files, the pack and index, rather than the loose objects.

Thanks for this, I have tried this out and while going through the surrounding documentation, found `transfer.unpackLimit`. This was exactly what I was looking for.

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> If you have a large number of references, you may wish to convert the
> repositories to use the reftable backend instead of the files backend
> (via `git refs migrate --ref-format=reftable`), which will also tend to
> use fewer files on disk.  Note that this requires a relatively new Git,
> so if you need to access these repositories with an older Git version,
> don't do this.
>
> You can also periodically repack more frequently if you set
> `gc.autoPackLimit` to a smaller number (in conjunction with
> `fetch.unpackLimit` above).  If you have repositories that are not
> packed at all, running `git gc` (or, if you don't want to remove any
> objects, `git repack -d --cruft`), which will likely reduce the number
> of loose objects and result in more objects being packed.

Yes, I have now set the following config surrounding gc

	[receive]
		autogc = true
	[gc]
		auto = 1
		autopacklimit = 1

Curious to know if this will have any noticable performance impact though. As I mentioned in my previous msg, these are small repos but the number of repos being created and the operations performed on them are large - mostly pushes,

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> Finally, it may be useful to you to reformat the underlying file system
> in a way that has more inodes.  I know ext4 supports a larger inode
> ratio for repositories with many small files.  Alternatively, apparently
> btrfs does not have a fixed inode ratio, so that may be helpful to avoid
> running out of inodes.  I can't speak to non-Linux file systems, though.

Unfourtunately, I can't reformat the NFS. It is currently on ext4 and even though there are quite a few filesystems which don't impose a threshold on inodes, I can't migrate to them.