JuiceFS元数据引擎PostgreSQL

使用PostgreSQL作为JuiceFS元数据引擎，各表的含义和字段做一个简单归纳

juicefs数据库用于存储juicefs文件信息

复制postgres=# \l
                                                      List of databases
   Name    |  Owner   | Encoding | Locale Provider |  Collate   |   Ctype    | ICU Locale | ICU Rules |   Access privileges
-----------+----------+----------+-----------------+------------+------------+------------+-----------+-----------------------
 juicefs   | juicefs  | UTF8     | libc            | en_US.utf8 | en_US.utf8 |            |           |

可以看到数据库包含了很多张表

juicefs=# \dt
              List of relations
 Schema |       Name        | Type  |  Owner
--------+-------------------+-------+---------
 public | jfs_acl           | table | juicefs
 public | jfs_chunk         | table | juicefs
 public | jfs_chunk_ref     | table | juicefs
 public | jfs_counter       | table | juicefs
 public | jfs_delfile       | table | juicefs
 public | jfs_delslices     | table | juicefs
 public | jfs_detached_node | table | juicefs
 public | jfs_dir_quota     | table | juicefs
 public | jfs_dir_stats     | table | juicefs
 public | jfs_edge          | table | juicefs
 public | jfs_flock         | table | juicefs
 public | jfs_node          | table | juicefs
 public | jfs_plock         | table | juicefs
 public | jfs_session2      | table | juicefs
 public | jfs_setting       | table | juicefs
 public | jfs_sustained     | table | juicefs
 public | jfs_symlink       | table | juicefs
 public | jfs_xattr         | table | juicefs
(18 rows)

• jfs_setting 存储文件系统格式化信息

  name  |                                                    value
--------+--------------------------------------------------------------------------------------------------------------
 format | {                                                                                                           +
        | "Name": "juicefs",                                                                                          +
        | "UUID": "6b1aaa0a-e3da-43db-ab4e-252a92f722bd",                                                             +
        | "Storage": "s3",                                                                                            +
        | "Bucket": "http://192.168.247.143:9000/bucket1",                                                            +
        | "AccessKey": "jAzkO6aquJlH8daWJ0vC",                                                                        +
        | "SecretKey": "UclQZeuePQcp9HmMd9Q0EUkL0QIb70ty9kPbbWRcpaYI0JjAUUsE6x8dZ4QxU3hLsK1EbesYB4DfJHeJzPzHUL+ch5A=",+
        | "BlockSize": 4096,                                                                                          +
        | "Compression": "none",                                                                                      +
        | "EncryptAlgo": "aes256gcm-rsa",                                                                             +
        | "KeyEncrypted": true,                                                                                       +
        | "TrashDays": 1,                                                                                             +
        | "MetaVersion": 1,                                                                                           +
        | "MinClientVersion": "1.1.0-A",                                                                              +
        | "DirStats": true,                                                                                           +
        | "EnableACL": false                                                                                          +
        | }
(1 row)

• jfs_edge 存储文件名、inode号及父目录inode号信息

 id | parent |     name     | inode | type
----+--------+--------------+-------+------
  1 |      1 | \x64697231   |     2 |    2
  2 |      1 | \x66696c6531 |     3 |    1
  3 |      2 | \x66696c6531 |     4 |    1
  4 |      2 | \x66696c6532 |     5 |    1
(4 rows)

• jfs_node 存储文件系统的基本元数据

        inode        | type | flags | mode | uid | gid |      atime       |      mtime       |      ctime       | atimensec | mtimensec | ctimensec | nlink | length | rdev | parent | access_acl_id | default_acl_id
---------------------+------+-------+------+-----+-----+------------------+------------------+------------------+-----------+-----------+-----------+-------+--------+------+--------+---------------+----------------
 9223372032828243968 |    2 |     0 |  365 |   0 |   0 | 1720746821874411 | 1720746821874411 | 1720746821874411 |       855 |       855 |       855 |     2 |   4096 |    0 |      1 |             0 |              0
                   1 |    2 |     0 |  511 |   0 |   0 | 1720746821874411 | 1720751372873926 | 1720751372873926 |       855 |       855 |       855 |     3 |   4096 |    0 |      1 |             0 |              0
                   3 |    1 |     0 |  420 |   0 |   0 | 1720751372873926 | 1720751372878651 | 1720751372885031 |        42 |        11 |       201 |     1 |      4 |    0 |      1 |             0 |              0
                   4 |    1 |     0 |  420 |   0 |   0 | 1720751407595564 | 1720751407598082 | 1720751407603477 |       450 |       178 |       346 |     1 |      9 |    0 |      2 |             0 |              0
                   2 |    2 |     0 |  493 |   0 |   0 | 1720750221908578 | 1720751416940112 | 1720751416940112 |       916 |       916 |       916 |     2 |   4096 |    0 |      1 |             0 |              0
                   5 |    1 |     0 |  420 |   0 |   0 | 1720751416940112 | 1720751416942616 | 1720751416946878 |       475 |       471 |       682 |     1 |     13 |    0 |      2 |             0 |              0
(6 rows)

• jfs_chunk 存储文件的块信息，slices分段记录着信息

 id | inode | indx |                       slices
----+-------+------+----------------------------------------------------
  1 |     3 |    0 | \x000000000000000000000001000000040000000000000004
  2 |     4 |    0 | \x000000000000000000000003000000090000000000000009
  3 |     5 |    0 | \x0000000000000000000000040000000d000000000000000d
(3 rows)

• jfs_chunk_ref chunkid与size可组成对象名

 chunkid | size | refs
---------+------+------
       1 |    4 |    1
       3 |    9 |    1
       4 |   13 |    1
(3 rows)

• jfs_counter 存储文件系统汇总计数信息

        name         |   value
---------------------+------------
 nextSession         |          5
 nextChunk           |       4097
 usedSpace           |      16384
 totalInodes         |          4
 lastCleanupFiles    | 1722842479
 lastCleanupSessions | 1722842515
 nextCleanupSlices   | 1722840923
 lastCleanupTrash    | 1722840440
 nextInode           |       1026
(9 rows)

• jfs_dir_stats 存储着各目录状态信息

 inode | data_length | used_space | used_inodes
-------+-------------+------------+-------------
     1 |           4 |       8192 |           2
     2 |          22 |       8192 |           2
(2 rows)

• jfs_symlink 存储符号链接的信息

 inode | target
-------+--------
(0 rows)

• jfs_xattr 存储扩展属性

 id | inode |    name    |                   value
----+-------+------------+--------------------------------------------
  1 |     1 | lastBackup | \x323032342d30382d30355430363a30383a34335a
(1 row)

• jfs_session2 存储客户端会话信息

 sid |   expire   |                    info
-----+------------+-------------------------------------------------------------
   5 | 1722841562 | \x7b2256657273696f6e223a22312e322e302b323032342d

• jfs_plock 存储文件锁的信息

 id | inode | sid | owner | records
----+-------+-----+-------+---------
(0 rows)

• jfs_delfile 存储删除文件信息

 inode | length | expire
-------+--------+--------
(0 rows)

• jfs_dir_quota 存储配额信息

 inode | max_space | max_inodes | used_space | used_inodes
-------+-----------+------------+------------+-------------
(0 rows)