[pbs-devel] [PATCH proxmox-backup 2/2] GC: raise nofile soft limit to the hard limit on s3 backed stores

[Fabian Grünbichler]

On November 18, 2025 11:45 am, Christian Ebner wrote:
> Since commit 86d5d073 ("GC: fix race with chunk upload/insert on s3
> backends"), per-chunk file locks are acquired during phase 2 of
> garbage collection for datastores backed by s3 object stores. This
> however means that up to 1000 file locks might be held at once, which
> can result in the limit of open file handles to be reached.
> 
> Therefore, bump the nolimit from the soft to the hard limit.
> 
> Signed-off-by: Christian Ebner <c.ebner at proxmox.com>
> ---
>  pbs-datastore/src/datastore.rs | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/pbs-datastore/src/datastore.rs b/pbs-datastore/src/datastore.rs
> index 0a5179230..ac22c10c5 100644
> --- a/pbs-datastore/src/datastore.rs
> +++ b/pbs-datastore/src/datastore.rs
> @@ -11,6 +11,7 @@ use http_body_util::BodyExt;
>  use hyper::body::Bytes;
>  use nix::unistd::{unlinkat, UnlinkatFlags};
>  use pbs_tools::lru_cache::LruCache;
> +use pbs_tools::raise_nofile_limit;
>  use tokio::io::AsyncWriteExt;
>  use tracing::{info, warn};
>  
> @@ -1589,6 +1590,12 @@ impl DataStore {
>          let s3_client = match self.backend()? {
>              DatastoreBackend::Filesystem => None,
>              DatastoreBackend::S3(s3_client) => {
> +                // required for per-chunk file locks in GC phase 2 on S3 backed stores
> +                let old_rlimit =
> +                    raise_nofile_limit().context("failed to raise open file handle limit")?;
> +                if old_rlimit.rlim_max <= 4096 {
> +                    info!("limit for open file handles low: {}", old_rlimit.rlim_max);
> +                }

shouldn't we just do this either in the service unit, or at service
startup, instead of during every GC run?

>                  proxmox_async::runtime::block_on(s3_client.head_bucket())
>                      .context("failed to reach bucket")?;
>                  Some(s3_client)
> -- 
> 2.47.3
> 
> 
> 
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