Large backups failing - 400 Bad Request: error reading a body from connection

[Stockdoodle]

I made a similar post here, but my issues weren't as resolved as I thought they were. Small container/vm backups finish w/o issue. I have two containers that each house about 2-3TB of data, plus a VM w/ another 3TB. All of their backups fail 100% of the time. PBS is running on bare hardware, but I had this same issue when it was running as a container on the PVE server (had a Linux Bridge between the two w/o an attached NIC). PVE and PBS servers are connected to the same switch (Unifi 48 port PoE). I have dual NICs on both servers aggregated w/ LCAP (issue persists when only single NIC is used on each). Backup and LAN traffic are on different VLANs. Datastore on PBS server is a ZFS mirror on two of these w/ a 3rd set as a spare (buying the capacity I need w/ SSDs is out of the question right now).

Things I've tried:

• Using single NICs instead of dual. Also set speed to 100FDX on switch for both.
• Jumbo frames on/off
• Turn TCP Offloading off
• Add special disk (SSD) to datastore's ZFS pool
• Running job w/ prlimit --nofile=1024:1024

Pings and iPerf tests between the two interfaces are both rock steady.

PBS job log

2026-08-16T16:06:11-05:00: upload_chunk done: 1283517 bytes, b11d406355bb61617b4317670fb9d2c372e3b377b4a19a359da165166869980b
2026-08-16T16:06:11-05:00: upload_chunk done: 8739809 bytes, 1bfe4f2ddd2a6958125917f25c1c9139c9571534fda166bc67aca929798e2114
2026-08-16T16:06:11-05:00: upload_chunk done: 1440806 bytes, 723a89e22b7e289e19c9a298fa495472557e166a3985b3989c6b2a79b37d632c
2026-08-16T16:06:11-05:00: POST /dynamic_chunk: 400 Bad Request: error reading a body from connection
2026-08-16T16:06:11-05:00: POST /dynamic_chunk: 400 Bad Request: error reading a body from connection
2026-08-16T16:06:11-05:00: POST /dynamic_chunk: 400 Bad Request: error reading a body from connection
2026-08-16T16:06:11-05:00: backup failed: connection error
2026-08-16T16:06:11-05:00: removing failed backup
2026-08-16T16:06:11-05:00: removing backup snapshot "/mnt/datastore/bu_store/ct/105/2026-08-16T21:03:20Z"
2026-08-16T16:06:11-05:00: POST /dynamic_chunk: 400 Bad Request: error reading a body from connection
2026-08-16T16:06:11-05:00: POST /dynamic_chunk: 400 Bad Request: error reading a body from connection
2026-08-16T16:06:11-05:00: POST /dynamic_chunk: 400 Bad Request: error reading a body from connection
2026-08-16T16:06:11-05:00: TASK ERROR: connection error: error:0A000119:SSL routines:tls_get_more_records:decryption failed or bad record mac:../ssl/record/methods/tls_common.c:873:, error:0A000139:SSL routines::record layer failure:../ssl/record/rec_layer_s3.c:698:

PVE job log

INFO: Upload config file '/var/tmp/vzdumptmp947904_105/etc/vzdump/pct.conf' to 'root@pam@192.168.5.3:8007:bu_store' as pct.conf.blob
INFO: Upload directory '/mnt/vzsnap0' to 'root@pam@192.168.5.3:8007:bu_store' as root.pxar.didx
INFO: processed 7.3 GiB in 1m, uploaded 7.208 GiB
INFO: processed 14.088 GiB in 2m, uploaded 13.998 GiB
INFO: HTTP/2.0 connection failed
INFO: unclosed encoder dropped
INFO: closed encoder dropped with state
INFO: unfinished encoder state dropped
INFO: finished encoder state with errors
INFO: catalog upload error - channel closed
INFO: Error: error:0A0003FC:SSL routines:ssl3_read_bytes:ssl/tls alert bad record mac:../ssl/record/rec_layer_s3.c:918:SSL alert number 20
INFO: cleanup temporary 'vzdump' snapshot
Logical volume "snap_vm-105-disk-0_vzdump" successfully removed.
ERROR: Backup of VM 105 failed - command 'lxc-usernsexec -m u:0:100000:65536 -m g:0:100000:65536 -- /usr/bin/proxmox-backup-client backup '--crypt-mode=encrypt' '--keyfd=15' pct.conf:/var/tmp/vzdumptmp947904_105/etc/vzdump/pct.conf root.pxar:/mnt/vzsnap0 --include-dev /mnt/vzsnap0/./ --include-dev /mnt/vzsnap0/./media --skip-lost-and-found '--exclude=/tmp/?*' '--exclude=/var/tmp/?*' '--exclude=/var/run/?*.pid' --backup-type ct --backup-id 105 --backup-time 1786914200 --entries-max 1048576 --repository root@pam@192.168.5.3:bu_store' failed: exit code 255
INFO: Failed at 2026-08-16 16:06:12
INFO: Backup job finished with errors
INFO: notified via target `gmail`
TASK ERROR: job errors