Re: [pbs-devel] [PATCH proxmox-backup v2] etc: provide and enable mount unit for /run/proxmox-backup

[Christian Ebner <c.ebner@proxmox.com>]

On 11/20/25 9:05 AM, Fabian Grünbichler wrote:
> On November 19, 2025 3:31 pm, Christian Ebner wrote:
>> Since the introduction of per-chunk file locks for datastores with s3
>> backend, the inodes on the tmpfs backing /run/proxmox-backup might be
>> to limited, the kernel dynamically calculating the limit based on
>> available system memory [0]. To not limit the number of inodes,
>> provide a systemd mount unit to create a dedicated tmpfs for
>> /run/proxmox-backup.
>>
>> The mount unit is only enabled but not started by dh_installsystemd,
>> so this has only effect after a reboot.
>>
>> [0] https://docs.kernel.org/filesystems/tmpfs.html
>>
>> Fixes: https://forum.proxmox.com/threads/176228/
>> Signed-off-by: Christian Ebner <c.ebner@proxmox.com>
> 
> Reviewed-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
> 
>> ---
>> Changes since version 1 (thanks @Fabian):
>> - Drop unneeded systemctl enable ...
>> - Add comment for why the inodes are unlimited
>> - Correctly set mountpoint uid:gid
>>
>>   debian/proxmox-backup-server.install |  1 +
>>   "etc/run-proxmox\\x2dbackup.mount"   | 14 ++++++++++++++
>>   2 files changed, 15 insertions(+)
>>   create mode 100644 "etc/run-proxmox\\x2dbackup.mount"
>>
>> diff --git a/debian/proxmox-backup-server.install b/debian/proxmox-backup-server.install
>> index d06f026cf..11dd037e8 100644
>> --- a/debian/proxmox-backup-server.install
>> +++ b/debian/proxmox-backup-server.install
>> @@ -6,6 +6,7 @@ etc/proxmox-backup-daily-update.timer /usr/lib/systemd/system/
>>   etc/proxmox-backup-proxy.service /usr/lib/systemd/system/
>>   etc/proxmox-backup.service /usr/lib/systemd/system/
>>   etc/removable-device-attach@.service /usr/lib/systemd/system/
>> +etc/run-proxmox\x2dbackup.mount /usr/lib/systemd/system/
>>   usr/bin/pmt
>>   usr/bin/pmtx
>>   usr/bin/proxmox-tape
>> diff --git "a/etc/run-proxmox\\x2dbackup.mount" "b/etc/run-proxmox\\x2dbackup.mount"
>> new file mode 100644
>> index 000000000..cad35594d
>> --- /dev/null
>> +++ "b/etc/run-proxmox\\x2dbackup.mount"
>> @@ -0,0 +1,14 @@
>> +[Unit]
>> +Description=Mount tmpfs at /run/proxmox-backup
>> +Conflicts=umount.target
>> +Before=local-fs.target umount.target
>> +
>> +[Mount]
>> +Type=tmpfs
>> +What=tmpfs
>> +Where=/run/proxmox-backup
>> +# Unlimited inodes as this stores per-chunk file locks
>> +Options=rw,nosuid,nodev,noexec,relatime,uid=34,gid=34,nr_inodes=0,mode=755,inode64
> 
> one small nit: this could use `backup` instead of `34` (although it's
> pretty much guaranteed to not matter, we do so in other parts of the
> code base as well..)

Okay, will resend with that adapted, thanks!


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