bin: add blockgroup report

[chapmanjacobd]

I don't know how useful you will find this to be. Feel free to close if you think it does not add value. I only made this because I wanted to learn more about btrfs

When running device remove, the difference is pretty extreme compared to btrfs device usage (2.70TiB vs 10.75TiB). So it could be useful in that situation, to get a better understanding of the btrfs device remove process which people complain about being slow but in reality it seems to be pretty fast; de usage is just not showing the whole picture:

sudo bin/btrfs-blockgroup-report /mnt/do /dev/sdd -u                                                                                                                                                   
/mnt/do          9.03TiB         39391 fs chunks                                                                                                                                                                                  
/dev/sdd         10.75TiB        11005 device blockgroup extents (28%)                                                                                                                                                            
                                                                                                                                                                                                                                  
Blockgroup usage:                                                                                                                                                                                                                 
/dev/sdd                                                                                                                                                                                                                          
         DATA                                                                                                                                                                                                                     
                 Data-device dependence: 2.70TiB                                                                                                                                                                                  
                 Blockgroups: 10992                                                                                                                                                                                               
                 Blockgroup packing:                                                                                                                                                                                              
                     0% packed ************************************************************ (4401)                                                                                                                                
                    10% packed ********************* (1578)                                                                                                                                                                       
                    20% packed ***************** (1247)                                                                                                                                                                           
                    30% packed ************* (980)                                                                                                                                                                                
                    40% packed ********** (776)                                                                                                                                                                                   
                    50% packed ******* (583)                                                                                                                                                                                      
                    60% packed ****** (458)                                                                                                                                                                                       
                    70% packed **** (335)                                                                                                                                                                                         
                    80% packed *** (265)                                                                                                                                                                                          
                    90% packed *** (290)                                                                                                                                                                                          
                   100% packed * (79)                                                                                                                                                                                             


         METADATA|RAID1
                 Data-device dependence: 5.28GiB
                 Blockgroups: 13
                 Blockgroup packing:
                    30% packed ******* (7)
                    40% packed **** (4)
                    50% packed ** (2)

$ sudo btrfs de usage /mnt/do
/dev/sda, ID: 1
   Device size:            16.37TiB
   Device slack:              0.00B
   Data,single:            15.63TiB
   Metadata,RAID1:         32.00GiB
   System,RAID1:           32.00MiB
   Unallocated:           722.91GiB

/dev/sdc, ID: 2
   Device size:            12.73TiB
   Device slack:              0.00B
   Data,single:            12.06TiB
   Metadata,RAID1:         19.00GiB
   System,RAID1:           32.00MiB
   Unallocated:           665.97GiB

/dev/sdd, ID: 4
   Device size:            12.73TiB
   Device slack:           12.73TiB
   Data,single:            10.73TiB
   Metadata,RAID1:         13.00GiB
   Unallocated:           -10.75TiB

The default mode is pretty quick and it only prints number of device extents which can be useful for planning the order of device remove commands; but for more thorough device introspection I added a --usage flag to iterate over all the device extents

$ sudo env PYTHONBREAKPOINT=ipdb.set_trace /home/xk/github/o/python-btrfs/bin/btrfs-blockgroup-report /mnt/do/
/mnt/do/ 	26.35TiB 	54048 fs chunks
/dev/sda 	16.11TiB 	54107 chunk extents (100%)
/dev/sdc 	12.47TiB 	37608 chunk extents (70%)
/dev/sdd 	12.47TiB 	24841 chunk extents (46%)
/dev/sdh 	11.79TiB 	12069 chunk extents (22%)

This is what the output looks like with the --usage flag (this part is slow, takes between 20 seconds to 5 mins to run):

$ sudo env PYTHONBREAKPOINT=ipdb.set_trace /home/xk/github/o/python-btrfs/bin/btrfs-blockgroup-report --usage /mnt/do/
/mnt/do/ 	26.35TiB 	54048 fs chunks
/dev/sda 	16.11TiB 	54107 chunk extents (100%)
/dev/sdc 	12.47TiB 	37608 chunk extents (70%)
/dev/sdd 	12.47TiB 	24841 chunk extents (46%)
/dev/sdh 	11.79TiB 	12069 chunk extents (22%)

Blockgroup usage:
/dev/sda
	DATA
		Chunks at least partially on disk: 53989
		Data-device dependance: 26.3TiB
		Approx. chunk percentage used:
		    0% packed ************************************************************ (6524 chunks)
		   10% packed ********************************************* (5368 chunks)
		   20% packed ********************************************* (5352 chunks)
		   30% packed ****************************************** (5042 chunks)
		   40% packed *************************************** (4795 chunks)
		   50% packed **************************************** (4884 chunks)
		   60% packed **************************************** (4943 chunks)
		   70% packed ************************************* (4700 chunks)
		   80% packed ************************************ (4606 chunks)
		   90% packed ******************************************************** (6202 chunks)
		  100% packed * (1573 chunks)

	METADATA|RAID1
		Chunks at least partially on disk: 116
		Data-device dependance: 68.3GiB
		Approx. chunk percentage used:
		   30% packed * (2 chunks)
		   40% packed *********** (14 chunks)
		   50% packed ***************************** (32 chunks)
		   60% packed ************************************************************ (64 chunks)
		   70% packed * (4 chunks)

	SYSTEM|RAID1
		Chunks at least partially on disk: 2
		Data-device dependance: 12.8MiB
		Approx. chunk percentage used:
		   20% packed * (2 chunks)


/dev/sdc
	DATA
		Chunks at least partially on disk: 37549
		Data-device dependance: 18.1TiB
		Approx. chunk percentage used:
		    0% packed ************************************************************ (4654 chunks)
		   10% packed ********************************************* (3753 chunks)
		   20% packed ********************************************* (3760 chunks)
		   30% packed ***************************************** (3560 chunks)
		   40% packed ************************************** (3377 chunks)
		   50% packed ************************************** (3390 chunks)
		   60% packed *************************************** (3447 chunks)
		   70% packed ************************************ (3237 chunks)
		   80% packed ********************************** (3107 chunks)
		   90% packed **************************************************** (4215 chunks)
		  100% packed * (1049 chunks)

	METADATA|RAID1
		Chunks at least partially on disk: 58
		Data-device dependance: 34.1GiB
		Approx. chunk percentage used:
		   30% packed * (1 chunks)
		   40% packed *********** (7 chunks)
		   50% packed ***************************** (16 chunks)
		   60% packed ************************************************************ (32 chunks)
		   70% packed * (2 chunks)

	SYSTEM|RAID1
		Chunks at least partially on disk: 1
		Data-device dependance: 6.4MiB
		Approx. chunk percentage used:
		   20% packed * (1 chunks)


/dev/sdd
	DATA
		Chunks at least partially on disk: 24782
		Data-device dependance: 11.8TiB
		Approx. chunk percentage used:
		    0% packed ************************************************************ (3163 chunks)
		   10% packed ********************************************** (2580 chunks)
		   20% packed ********************************************* (2535 chunks)
		   30% packed **************************************** (2333 chunks)
		   40% packed ************************************** (2247 chunks)
		   50% packed ************************************* (2215 chunks)
		   60% packed ************************************** (2243 chunks)
		   70% packed ************************************ (2158 chunks)
		   80% packed ********************************* (2037 chunks)
		   90% packed ************************************************ (2674 chunks)
		  100% packed * (597 chunks)

	METADATA|RAID1
		Chunks at least partially on disk: 58
		Data-device dependance: 34.1GiB
		Approx. chunk percentage used:
		   30% packed * (1 chunks)
		   40% packed *********** (7 chunks)
		   50% packed ***************************** (16 chunks)
		   60% packed ************************************************************ (32 chunks)
		   70% packed * (2 chunks)

	SYSTEM|RAID1
		Chunks at least partially on disk: 1
		Data-device dependance: 6.4MiB
		Approx. chunk percentage used:
		   20% packed * (1 chunks)


/dev/sdh
	DATA
		Chunks at least partially on disk: 12010
		Data-device dependance: 5.4TiB
		Approx. chunk percentage used:
		    0% packed ************************************************************ (1658 chunks)
		   10% packed ************************************************ (1386 chunks)
		   20% packed ******************************************* (1266 chunks)
		   30% packed **************************************** (1192 chunks)
		   40% packed *********************************** (1064 chunks)
		   50% packed ************************************ (1073 chunks)
		   60% packed ************************************ (1074 chunks)
		   70% packed ********************************** (1045 chunks)
		   80% packed ***************************** (909 chunks)
		   90% packed *************************************** (1149 chunks)
		  100% packed * (194 chunks)

	METADATA|RAID1
		Chunks at least partially on disk: 58
		Data-device dependance: 34.1GiB
		Approx. chunk percentage used:
		   30% packed * (1 chunks)
		   40% packed *********** (7 chunks)
		   50% packed ***************************** (16 chunks)
		   60% packed ************************************************************ (32 chunks)
		   70% packed * (2 chunks)

	SYSTEM|RAID1
		Chunks at least partially on disk: 1
		Data-device dependance: 6.4MiB
		Approx. chunk percentage used:
		   20% packed * (1 chunks)

You can compare this to the output of the fs usage-report:

sudo btrfs-usage-report /mnt/do
Btrfs usage report for /mnt/do
Filesystem ID: 8da156d7-abd4-4c84-a2f0-8c17f43eb60c
Mixed groups: False

Total physical space usage:
| 
| Total filesystem size: 56.21TiB
| Allocated bytes: 52.86TiB
| Allocatable bytes remaining: 3.35TiB

Target profiles:
|
| type         profile     
| ----         -------     
| System       RAID1       
| Metadata     RAID1       
| Data         single      

Estimated virtual space left for use:
|
| type         free        
| ----         ----        
| Data         29.66TiB    
| MetaData     31.73GiB    

Virtual space usage by block group type:
|
| type                total         used
| ----                -----         ----
| Data             52.75TiB     26.42TiB
| System           32.00MiB      6.39MiB
| Metadata         58.00GiB     34.27GiB

Allocated raw disk bytes by chunk type.
|
| flags               allocated         used    parity *)
| -----               ---------         ----    ---------
| DATA                 52.75TiB     26.42TiB        0.00B
| SYSTEM|RAID1         64.00MiB     12.78MiB        0.00B
| METADATA|RAID1      116.00GiB     68.54GiB        0.00B
|
| *) Parity is a reserved part of the allocated bytes, limiting the
|    amount that can be used for data or metadata.

Allocated bytes per device:
|
| devid      total size    allocated path
| -----      ----------    --------- ----
| 1            16.37TiB     16.11TiB /dev/sda
| 2            12.73TiB     12.47TiB /dev/sdc
| 4            12.73TiB     12.47TiB /dev/sdd
| 5            14.37TiB     11.81TiB /dev/sdh

Allocated bytes per device, split up by chunk type.
|
| Device ID: 1
| | flags               allocated    parity *)
| | -----               ---------    ---------
| | DATA                 16.05TiB        0.00B
| | METADATA|RAID1       58.00GiB        0.00B
| | SYSTEM|RAID1         32.00MiB        0.00B
|
| Device ID: 2
| | flags               allocated    parity *)
| | -----               ---------    ---------
| | DATA                 12.47TiB        0.00B
|
| Device ID: 4
| | flags               allocated    parity *)
| | -----               ---------    ---------
| | DATA                 12.47TiB        0.00B
|
| Device ID: 5
| | flags               allocated    parity *)
| | -----               ---------    ---------
| | DATA                 11.75TiB        0.00B
| | METADATA|RAID1       58.00GiB        0.00B
| | SYSTEM|RAID1         32.00MiB        0.00B
|
| *) Parity is a reserved part of the allocated bytes, limiting the
|    amount that can be used for data or metadata.

Unallocatable raw disk space:
|
| Reclaimable (by using balance): 0.00B
| Not reclaimable (because of different disk sizes): 0.00B

Unallocatable bytes per device, given current target profiles:
|
| devid         soft *)     hard **) reclaimable ***)
| -----         -------     -------- ----------------
| 1               0.00B        0.00B            0.00B
| 2               0.00B        0.00B            0.00B
| 4               0.00B        0.00B            0.00B
| 5               0.00B        0.00B            0.00B
|
|   *) Because allocations in the filesystem are unbalanced.
|  **) Because of having different sizes of devices attached.
| ***) Amount of 'soft' unallocatable space that can be reclaimed,
|      before hitting the 'hard' limit.

I'm not sure why there are slightly more device blockgroups than fs chunks:

sudo env PYTHONBREAKPOINT=ipdb.set_trace /home/xk/github/o/python-btrfs/bin/btrfs-blockgroup-report --usage /mnt/d2/
/mnt/d2/ 	10.66TiB 	10929 fs chunks
/dev/sde1 	10.69TiB 	10947 device blockgroup extents (100%)

Blockgroup usage:
/dev/sde1
	DATA
		Blockgroups at least partially on disk: 10911
		Data-device dependance: 10.65TiB
		Approx. blockgroup percentage packed:
		    0% packed * (1)
		   40% packed * (1)
		   70% packed * (7)
		   80% packed * (20)
		   90% packed * (141)
		  100% packed ************************************************************ (10741)


	METADATA|DUP
		Blockgroups at least partially on disk: 34
		Data-device dependance: 32.11GiB
		Approx. blockgroup percentage packed:
		    0% packed * (2)
		  100% packed ************************************************************ (32)


	SYSTEM|DUP
		Blockgroups at least partially on disk: 2
		Data-device dependance: 2.38MiB
		Approx. blockgroup percentage packed:
		    0% packed * (2)