[pbs-devel] [PATCH proxmox-backup v3] etc: raise nofile soft limit to hard limit for proxmox-backup-proxy

[Christian Ebner]

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 NOFILE soft limit for the proxmox-backup-proxy in
the systemd service unit, while keeping the hard limit as defined in
/etc/systemd/system.conf.

This is acceptable since PBS does not directly depend on problematic
select() calls as verified via `nm` and does not use it in linked
libraries to the best of my knowledge.

Occurrences of the symbol according to `nm -D <shared-object>` are:

/lib/x86_64-linux-gnu/libapt-pkg.so.7.0
                 U select at GLIBC_2.2.5
/lib/x86_64-linux-gnu/libpam.so.0
                 U select at GLIBC_2.2.5
/lib/x86_64-linux-gnu/libc.so.6
000000000010e140 W select@@GLIBC_2.2.5
/lib/x86_64-linux-gnu/libcrypto.so.3
                 U select at GLIBC_2.2.5

[0] https://github.com/systemd/systemd/blob/main/NEWS#L12044

Signed-off-by: Christian Ebner <c.ebner at proxmox.com>
---
Changes since version 2:
- But soft to hard limit
- Extend commit message with respect to select()

 etc/proxmox-backup-proxy.service.in | 1 +
 1 file changed, 1 insertion(+)

diff --git a/etc/proxmox-backup-proxy.service.in b/etc/proxmox-backup-proxy.service.in
index 7ca806aa4..8e4bbc197 100644
--- a/etc/proxmox-backup-proxy.service.in
+++ b/etc/proxmox-backup-proxy.service.in
@@ -10,6 +10,7 @@ Type=notify
 ExecStart=%LIBEXECDIR%/proxmox-backup/proxmox-backup-proxy
 ExecReload=/bin/kill -HUP $MAINPID
 PIDFile=/run/proxmox-backup/proxy.pid
+LimitNOFILE=524288
 Restart=on-failure
 User=%PROXY_USER%
 Group=%PROXY_USER%
-- 
2.47.3