Provided by: vmfs6-tools_0.2.0-1_amd64 bug


       debugvmfs6 - VMFS file system debugger


       debugvmfs6 VOLUME... COMMAND [ OPTIONS ] debugvmfs6 -b BITMAP show [ VARIABLE ]


       The debugvmfs6 program allows to display various informations about VMFS6 file systems,
       and to access data within the file systems.

       The VOLUME to be opened can be either a block device or an image file. When the VMFS
       spreads accross several extents, all extents must be given.

       Please note that most commands are still likely to change in future versions.

       When given the -b option, a BITMAP file may directly be opened from the host file system.
       In this mode, only the show command is supported, and the variables available are only a


       Some commands take a filespec as an argument. A filespec may take either of the following

       •   A path name, relative to the root of the filesystem if it starts with '/', or relative
           to the current working directory otherwise (interactive mode only).

       •   An inode number, enclosed between angle brackets, e.g. '<4>', '<0x1400004>'


       cat filespec [ ... ]
           Outputs the content of the given files from the VMFS.

       ls [ -l ] filespec
           Lists files contained at the given location within the VMFS.

           With -l, gives some more information, much like the output from ls(1) when given the
           -l option.

       truncate filespec length
           Truncate the file to the specified length. R/W support must be enabled.

       chmod filespec mode
           Change file permissions to the given mode.

           Outputs information about file system size.

       get_file_block filespec position
           Get file block corresponding to position in the specified file.

           Checks volume bitmaps consistency.

           Outputs active heartbeats on the file system.

       read_block block_id [ ... ]
           Outputs content within the specified block_id in binary

       get_block_status block_id
           Get status (allocated or free) of the specified block_id.

       alloc_block_fixed block_id
           Allocate the specified block_id. R/W support must be enabled.

       alloc_block block_type
           Allocate a block of the specified type. R/W support must be enabled.

           Allowed block types are: 1 (File Block), 2 (Sub-Block), 3 (Pointer Block) and 4 (File
           Descriptor / Inode).

       free_block block_id
           Free the specified block_id. R/W support must be enabled.

           Warning: can cause damage since no heartbeat is used at this time and a block used by
           a file can be freed.

           Display value(s) of the given variable. See the VARIABLES section for more details.
           When no variable is given, it lists the top-level properties.

           Starts an interactive session. All of the above commands can be executed from within
           the interactive session.

           The current working directory can be changed with the cd command, followed by a

           The following output redirections are supported within the shell:

           •   cmd > output

               Puts the output of cmd in the output file.

           •   cmd >> output

               Appends the output of cmd to the output file.

           •   cmd | external command

               Sends the output of cmd to the input of external command. The external command
               itself can contain output redirection.


               •   read_block 0x00000681 | less

               •   cat /.fdc.sf | hexdump -C

               •   cat /.fdc.sf | hexdump -C > /tmp/fdc.hex

               •   cat /.fdc.sf | hexdump -C | less


       Variables in debugvmfs6 represent structures on the filesystem. The currently supported
       top-level variables are the following:

       •   vol_versionversionlabelmodeuuidctimeblock_sizesubblock_sizefdc_header_sizefdc_bitmap_countfbbfdcpbcsbcfslvmblkid[blk]

       •   dirent["path"]

       •   inode["filespec"]

       The vol_version, version, label, mode, uuid, ctime, block_size, subblock_size,
       fdc_header_size, and fdc_bitmap_count properties are low-level information about the

       The fbb, fdc, pbc and sbc variables are bitmaps. Running them through the show command
       will display all the bitmaps header fields. Each of these fields can also be displayed

       •   bitmap.items_per_bitmap_entrybitmap.bmp_entries_per_areabitmap.hdr_sizebitmap.data_sizebitmap.area_sizebitmap.area_countbitmap.total_itemsbitmap.used_itemsbitmap.free_itemsbitmap.entry[n]

       e.g. to display the data size of the fdc bitmap, type show fdc.data_size.

       Each bitmap.entry[n] (where 0 ≤ n < bitmap.bmp_entries_per_area * bitmap.area_count)
       contains information about each entry in the bitmap. The available fields are:

       •   bitmap.entry[n].id

       •   bitmap.entry[n].total

       •   bitmap.entry[n].free

       •   bitmap.entry[n].ffree

       •   bitmap.entry[n].mdh

       •   bitmap.entry[n].item[m]

       The bitmap.entry[n].mdh is a metadata header. See further below for more details about
       metadata headers.

       Each bitmap.entry[n].item[m] (where 0 ≤ m < bitmap.items_per_bitmap_entry) contains
       information about a given item in the given entry. The available fields are:

       •   bitmap.entry[n].item[m].used

       •   bitmap.entry[n].item[m].dump

       The pbc bitmap has an additional field:

       •   pbc.entry[n].item[m].blocks

       The lvm variable contains low-level information about the physical and logical volumes.
       The available fields are:

       •   lvm.uuidlvm.sizelvm.blockslvm.num_extentslvm.extent[n]

       Each lvm.extent[n] (where 0 ≤ n < lvm.num_extents) contains low-level information about
       the physical volumes. The available fields are:

       •   lvm.extent[n].device

       •   lvm.extent[n].uuid

       •   lvm.extent[n].lun

       •   lvm.extent[n].version

       •   lvm.extent[n].name

       •   lvm.extent[n].size

       •   lvm.extent[n].num_segments

       •   lvm.extent[n].first_segment

       •   lvm.extent[n].last_segment

       Each blkid[blk] (where blk is a block id) contains information on the given block id. The
       available fields are:

       •   blkid[blk].item

       •   blkid[blk].flags

       Each dirent[path] (where path is a path relative to the current directory in the shell or
       / outside the shell) contains information on the directory entry corresponding to the
       given path. The available fields are:

       •   dirent["path"].type

       •   dirent["path"].block_id

       •   dirent["path"].record_id

       •   dirent["path"].name

       Each inode[filespec] contains information on the inode corresponding to the given
       filespec. The available fields are:

       •   inode["filespec"].id

       •   inode["filespec"].id2

       •   inode["filespec"].nlink

       •   inode["filespec"].type

       •   inode["filespec"].flags

       •   inode["filespec"].size

       •   inode["filespec"].blk_size

       •   inode["filespec"].blk_count

       •   inode["filespec"].uid

       •   inode["filespec"].gid

       •   inode["filespec"].mode

       •   inode["filespec"].zla

       •   inode["filespec"].tbz

       •   inode["filespec"].cow

       •   inode["filespec"].atime

       •   inode["filespec"].mtime

       •   inode["filespec"].ctime

       •   inode["filespec"].rdm_id

       •   inode["filespec"].mdh

       •   inode["filespec"].blocks

       Metadata headers are being used in several places, such as bitmap.entry[n].mdh and
       inode["filespec"].mdh. They mostly contain information about clustered accesses to
       metadata on the filesystem. The available fields are:

       •   mdh.magic

       •   mdh.pos

       •   mdh.hb_pos

       •   mdh.hb_lock

       •   mdh.hb_uuid

       •   mdh.hb_seq

       •   mdh.obj_seq

       •   mdh.mtime

       Variable values can also be used in expressions using square brackets to use the variable
       value as an index. For example:

       •   blkid[inode["filespec"].id]

       Enclosing a variable name with parentheses will use that variable value as a variable
       name. For example:

       •   (blkid[blk].item).status

       When invoked with the -b option, the top-level variables are those normally under bitmap:

       •   items_per_bitmap_entrybmp_entries_per_areahdr_sizedata_sizearea_sizearea_counttotal_itemsused_itemsfree_itemsentry[n]

       The sub-variables for each entry are also available.


       Christophe Fillot <[1]>, Mike Hommey <[2]> Weafon Tsao
       <[3]> Thomas Ward <[4]>








  0.0.0-patched                             04/05/2022                              DEBUGVMFS6(8)