I’m seeing extremely poor performance when restoring files from a pxar archive with proxmox-backup-client catalog shell and restore-selected.
Environment
Problem
I entered the catalog shell and selected a path inside the pxar archive:
proxmox-backup-client catalog shell host/pbs-host/2026-04-14T21:56:47Z data1.pxar --ns data
select /pwrp/hllprd/src/db
restore-selected /tmp/testrestore/test10
Initially, running this as a normal user appeared to hang indefinitely. After leaving it overnight, it eventually failed with:
Error: failed to set ownershipCaused by: Operation not permitted (os error 1)
When I ran the catalog shell with "sudo -E" prefixed, it did complete and preserved ownership correctly:
-rw-rw-r-- 1 user pwrp 278K Oct 15 2025 testrestore/pwrp/hllprd/src/db/cvolhllprd.wb_load
The restored file above is only about 278 KB, but the restore took about 90 minutes!
The same directory, restored/downloaded from the PBS web UI, completed in about 30 seconds.
So there seems to be a very large performance gap between the web UI and the proxmox-backup-client tool.
Debugging
With PBS_LOG=debug, the client produced a huge number of repeating HTTP/2 log lines like:
Connection: send frame=Headers { stream_id: StreamId(3935), flags: (0x5: END_HEADERS | END_STREAM) } peer=ClientConnection: received frame=Headers { stream_id: StreamId(3935), flags: (0x4: END_HEADERS) } peer=ClientConnection: received frame=Data { stream_id: StreamId(3935), flags: (0x1: END_STREAM) } peer=Client
This continued with thousands of stream IDs, couldn't pull anything useful from it.
While the restore was running, iostat -x 1 on the PBS server showed only a short burst of activity and then mostly idle disks/CPU. The server did not appear to be under meaningful sustained load.
iperf3 from client to PBS:
[ 5] 0.00-10.00 sec 869 MBytes 729 Mbits/sec 1001 retr sender
[ 5] 0.00-10.00 sec 868 MBytes 728 Mbits/sec receiver
Client benchmark
proxmox-backup-client benchmark from the client gave:
Uploaded 110 chunks in 5 seconds.
Time per request: 52411 microseconds.
TLS speed: 80.03 MB/s
SHA256 speed: 4452.42 MB/s
Compression speed: 639.65 MB/s
Decompress speed: 913.52 MB/s
AES256/GCM speed: 8130.86 MB/s
Verify speed: 792.19 MB/s
Setup
Client:
Environment
- Client package: proxmox-backup-client 4.1.5-1
- Installed from: http://download.proxmox.com/debian/pbs-client trixie/main
- Backup server: proxmox-backup-server 4.1.6-1 running version: 4.1.6
Problem
I entered the catalog shell and selected a path inside the pxar archive:
proxmox-backup-client catalog shell host/pbs-host/2026-04-14T21:56:47Z data1.pxar --ns data
select /pwrp/hllprd/src/db
restore-selected /tmp/testrestore/test10
Initially, running this as a normal user appeared to hang indefinitely. After leaving it overnight, it eventually failed with:
Error: failed to set ownershipCaused by: Operation not permitted (os error 1)
When I ran the catalog shell with "sudo -E" prefixed, it did complete and preserved ownership correctly:
-rw-rw-r-- 1 user pwrp 278K Oct 15 2025 testrestore/pwrp/hllprd/src/db/cvolhllprd.wb_load
The restored file above is only about 278 KB, but the restore took about 90 minutes!
The same directory, restored/downloaded from the PBS web UI, completed in about 30 seconds.
So there seems to be a very large performance gap between the web UI and the proxmox-backup-client tool.
Debugging
With PBS_LOG=debug, the client produced a huge number of repeating HTTP/2 log lines like:
Connection: send frame=Headers { stream_id: StreamId(3935), flags: (0x5: END_HEADERS | END_STREAM) } peer=ClientConnection: received frame=Headers { stream_id: StreamId(3935), flags: (0x4: END_HEADERS) } peer=ClientConnection: received frame=Data { stream_id: StreamId(3935), flags: (0x1: END_STREAM) } peer=Client
This continued with thousands of stream IDs, couldn't pull anything useful from it.
While the restore was running, iostat -x 1 on the PBS server showed only a short burst of activity and then mostly idle disks/CPU. The server did not appear to be under meaningful sustained load.
iperf3 from client to PBS:
[ 5] 0.00-10.00 sec 869 MBytes 729 Mbits/sec 1001 retr sender
[ 5] 0.00-10.00 sec 868 MBytes 728 Mbits/sec receiver
Client benchmark
proxmox-backup-client benchmark from the client gave:
Uploaded 110 chunks in 5 seconds.
Time per request: 52411 microseconds.
TLS speed: 80.03 MB/s
SHA256 speed: 4452.42 MB/s
Compression speed: 639.65 MB/s
Decompress speed: 913.52 MB/s
AES256/GCM speed: 8130.86 MB/s
Verify speed: 792.19 MB/s
Setup
Client:
- 1 Gbit NIC
- MTU 1500
- Ping to PBS: avg 0.248 ms, 0% loss
- Intel Ultra 5 225T + integrated graphics
- bond0 at 20 Gbit
- member links at 10 Gbit each
- MTU 1500
- Intel Xeon Silver 4214 CPU @ 2.20GHz
