Hello,
i have new 32GB SSD in my intel nuc, installed debian9 on it, using btrfs as a rootfs.
Then i created subvolumes /system and /home and moved system there.
System was installed using kernel 4.9.x and filesystem created using btrfs-progs 4.7.x
Details follow:
main filesystem
# btrfs filesystem usage /mnt/btrfs/ssd/
Overall:
Device size: 29.08GiB
Device allocated: 4.28GiB
Device unallocated: 24.80GiB
Device missing: 0.00B
Used: 2.54GiB
Free (estimated): 26.32GiB (min: 26.32GiB)
Data ratio: 1.00
Metadata ratio: 1.00
Global reserve: 16.00MiB (used: 0.00B)
Data,single: Size:4.00GiB, Used:2.48GiB
/dev/sda3 4.00GiB
Metadata,single: Size:256.00MiB, Used:61.05MiB
/dev/sda3 256.00MiB
System,single: Size:32.00MiB, Used:16.00KiB
/dev/sda3 32.00MiB
Unallocated:
/dev/sda3 24.80GiB
#/etc/fstab
UUID=d801da52-813d-49da-bdda-87fc6363e0ac /mnt/btrfs/ssd btrfs noatime,space_cache=v2,compress=lzo,commit=300,subvolid=5 0 0
UUID=d801da52-813d-49da-bdda-87fc6363e0ac / btrfs noatime,space_cache=v2,compress=lzo,commit=300,subvol=/system 0 0
UUID=d801da52-813d-49da-bdda-87fc6363e0ac /home btrfs noatime,space_cache=v2,compress=lzo,commit=300,subvol=/home 0 0
-----
Then i installed kernel from backports:
4.18.0-0.bpo.1-amd64 #1 SMP Debian 4.18.6-1~bpo9+1
and btrfs-progs 4.17
For backups , i have created 16GB iscsi device on my qnap and mounted it, created filesystem, mounted like this:
LABEL=backup /mnt/btrfs/backup btrfs noatime,space_cache=v2,compress=lzo,subvolid=5,nofail,noauto 0 0
After send-receive operation on /home subvolume, usage looks like this:
# btrfs filesystem usage /mnt/btrfs/backup/
Overall:
Device size: 16.00GiB
Device allocated: 1.27GiB
Device unallocated: 14.73GiB
Device missing: 0.00B
Used: 844.18MiB
Free (estimated): 14.92GiB (min: 14.92GiB)
Data ratio: 1.00
Metadata ratio: 1.00
Global reserve: 16.00MiB (used: 0.00B)
Data,single: Size:1.01GiB, Used:833.36MiB
/dev/sdb 1.01GiB
Metadata,single: Size:264.00MiB, Used:10.80MiB
/dev/sdb 264.00MiB
System,single: Size:4.00MiB, Used:16.00KiB
/dev/sdb 4.00MiB
Unallocated:
/dev/sdb 14.73GiB
Problem is, during send-receive of system subvolume, it runs out of space:
# btrbk run /mnt/btrfs/ssd/system/ -v
btrbk command line client, version 0.26.1 (Wed Oct 17 09:51:20 2018)
Using configuration: /etc/btrbk/btrbk.conf
Using transaction log: /var/log/btrbk.log
Creating subvolume snapshot for: /mnt/btrfs/ssd/system
[snapshot] source: /mnt/btrfs/ssd/system
[snapshot] target: /mnt/btrfs/ssd/_snapshots/system.20181017T0951
Checking for missing backups of subvolume "/mnt/btrfs/ssd/system" in "/mnt/btrfs/backup/"
Creating subvolume backup (send-receive) for: /mnt/btrfs/ssd/_snapshots/system.20181016T2034
No common parent subvolume present, creating full backup...
[send/receive] source: /mnt/btrfs/ssd/_snapshots/system.20181016T2034
[send/receive] target: /mnt/btrfs/backup/system.20181016T2034
mbuffer: error: outputThread: error writing to <stdout> at offset 0x4b5bd000: Broken pipe
mbuffer: warning: error during output to <stdout>: Broken pipe
WARNING: [send/receive] (send=/mnt/btrfs/ssd/_snapshots/system.20181016T2034, receive=/mnt/btrfs/backup) At subvol /mnt/btrfs/ssd/_snapshots/system.20181016T2034
WARNING: [send/receive] (send=/mnt/btrfs/ssd/_snapshots/system.20181016T2034, receive=/mnt/btrfs/backup) At subvol system.20181016T2034
ERROR: rename o77417-5519-0 -> lib/modules/4.18.0-0.bpo.1-amd64/kernel/drivers/watchdog/pcwd_pci.ko failed: No space left on device
ERROR: Failed to send/receive btrfs subvolume: /mnt/btrfs/ssd/_snapshots/system.20181016T2034 -> /mnt/btrfs/backup
[delete] options: commit-after
[delete] target: /mnt/btrfs/backup/system.20181016T2034
WARNING: Deleted partially received (garbled) subvolume: /mnt/btrfs/backup/system.20181016T2034
ERROR: Error while resuming backups, aborting
Created 0/2 missing backups
WARNING: Skipping cleanup of snapshots for subvolume "/mnt/btrfs/ssd/system", as at least one target aborted earlier
Completed within: 116s (Wed Oct 17 09:53:16 2018)
--------------------------------------------------------------------------------
Backup Summary (btrbk command line client, version 0.26.1)
Date: Wed Oct 17 09:51:20 2018
Config: /etc/btrbk/btrbk.conf
Filter: subvolume=/mnt/btrfs/ssd/system
Legend:
=== up-to-date subvolume (source snapshot)
+++ created subvolume (source snapshot)
--- deleted subvolume
*** received subvolume (non-incremental)
>>> received subvolume (incremental)
--------------------------------------------------------------------------------
/mnt/btrfs/ssd/system
+++ /mnt/btrfs/ssd/_snapshots/system.20181017T0951
!!! /mnt/btrfs/backup/system.20181016T2034
!!! Target "/mnt/btrfs/backup" aborted: Failed to send/receive subvolume
NOTE: Some errors occurred, which may result in missing backups!
Please check warning and error messages above.
-----------------------------
With compression=none or compression=zlib , send-receive runs ok
Usage looks like this (after transfer):
# btrfs filesystem usage /mnt/btrfs/backup/
Overall:
Device size: 16.00GiB
Device allocated: 2.27GiB
Device unallocated: 13.73GiB
Device missing: 0.00B
Used: 1.64GiB
Free (estimated): 14.15GiB (min: 14.15GiB)
Data ratio: 1.00
Metadata ratio: 1.00
Global reserve: 16.00MiB (used: 0.00B)
Data,single: Size:2.01GiB, Used:1.59GiB
/dev/sdb 2.01GiB
Metadata,single: Size:264.00MiB, Used:54.20MiB
/dev/sdb 264.00MiB
System,single: Size:4.00MiB, Used:16.00KiB
/dev/sdb 4.00MiB
Unallocated:
/dev/sdb 13.73GiB
I will stick to zlib for now, i just wanted to report this
Thanks,
Libor
