xref: /dragonfly/tools/tools/hammer-backup/README (revision 335b9e93) 
11. What is hammer-backup?
2
3This script operates HAMMER PFSes and dumps its contents for backup
4purposes.
5
6It uses mirror-read directive (see 'man 8 hammer') to perform a
7dump to stdout that is redirected to a file with or without
8compression.
9
10It can take two types of backup:
11
12  a) Full: Where ALL the data of the PFS is sent to a file.
13  b) Inremental: It requires a previous full backup.
14
15Additionally to the backup data itself, it creates a .bkp file
16which contains metadata relative to the full and/or incremental
17backups.
18
19The format is the following
20
21  filename,rsv01,rsv02,backup type,shared uuid,last TID,md5 hash
22
23  filename   : Backup data file file.
24  rsv01,rsv02: Reserved fields
25  backup type: 1 or 2 (full or incremental, respectively)
26  shared uuid: PFS shared UUID for mirror ops
27  last TID   : Last transaction ID. Next incr. backup starting TID
28  md5 hash   : For restoring purposes
29
30Example:
31  $ head -1 20140305222026_pfs_t1_full.xz.bkp
32  20140305222026_pfs_t1_full.xz.bkp,,,f,e8decfc5-a4ab-11e3-942b-f56d04d293e0,000000011b36be30,05482d26644bd1e76e69d83002e08258
33
342. How to use it?
35
36General usage.
37
38Usage: hammer-backup.sh [-h] [-l] [-v] [-i <full-backup-file>] [-f] [-c <compress-rate>] -d [<backup-dir>] <path-to-PFS>
39
40 -h: Help outputo above.
41 -v: Verbose
42 -i <full-backup-file>: Incremental backup. Needs the full backup metadata file.
43                        Relative path to -d. You can specify 'auto' and the
44                        script should determine what's the latest full backup.
45 -f: Full backup
46 -c: Compress rate for xz(1)
47 -d: Backup directory
48 -l: List backups from backup directory.
49 -k: Validates integrity of all backup files.
50 <path-to-PFS>: PFS path to backup
51
522.1 Performing a full backup
53
54# ./hammer-backup -v -f -c 6 -d /root/backups /pfs/var
55INFO: Full backup.
56INFO: XZ compression level 6.
57INFO: Backup directory is /root/backups.
58INFO: Validating PFS
59INFO: Initiating full backup
60INFO: Launching: hammer -y -v mirror-read /pfs/var  2> /tmp/tmp.UdOwvYhv         | xz -c -6 > /root/backups/20140308001146_pfs_var.xz
61INFO: Backup completed.
62
63NOTE: -v is optional. Also note /pfs/var is found in standard installations.
64
652.2 Perform an incremental backup over a full one
66
67First list the backups available:
68
69# ./hammer-backup -l -d /root/backups
7020140308001146_pfs_var.xz.bkp:
71 full: 20140308001146_pfs_var.xz endtid: 0x000000011db6dc20 md5: 303ee864f4a747d9da7d556e83b05de5
72
73You can then specify the .bkp file you want. See the timestamp, and the path to
74PFS separated by '_' are embedded to it.
75
76# ./hammer-backup -c 6 -v -i 20140308001146_pfs_var.xz.bkp -d /root/backups /pfs/var
77INFO: Incremental backup.
78INFO: Backup directory is /root/backups.
79INFO: Validating PFS
80INFO: Initiating incremental backup
81INFO: Launching: hammer -y -v mirror-read /pfs/var 0x000000011db6dc20 2> /tmp/tmp.AleUwNnA       | xz -c -6 > /root/backups/20140308002450_pfs_var.xz
82INFO: Backup completed.
83
84# ./hammer-backup -l -d /root/backups
8520140308001146_pfs_var.xz.bkp:
86 full: 20140308001146_pfs_var.xz endtid: 0x000000011db6dc20 md5: 303ee864f4a747d9da7d556e83b05de5
87        incr: 20140308002450_pfs_var.xz endtid: 0x000000011db6e440 md5: 7a7c2799b880a293f2c8270c6a9b22aa
88
893.0 Recovering a PFS.
90
91If you are very familiar with HAMMER you can do it manually, so following our
92previous example:
93
94 - Locate the backup we want to recover.
95   # ./hammer-backup -l -d /root/backups
96   20140308001146_pfs_var.xz.bkp:
97    full: 20140308001146_pfs_var.xz endtid: 0x000000011db6dc20 md5: 303ee864f4a747d9da7d556e83b05de5
98         incr: 20140308002450_pfs_var.xz endtid: 0x000000011db6e440 md5: 7a7c2799b880a293f2c8270c6a9b22aa
99
100 - Mirror-write the files in the correct order. First the full, then the
101   incremental ones. NOTE: -y on the hammer command will actually create
102   a slave PFS.
103   # unxz -c /root/backups/20140308001146_pfs_var.xz | hammer -y mirror-write /pfs/var_2
104   PFS slave /pfs/var_2 does not exist. Auto create new slave PFS!
105   Creating PFS #10        succeeded!
106   /pfs/var_2
107       sync-beg-tid=0x0000000000000001
108       sync-end-tid=0x0000000000000001
109       shared-uuid=ce020232-9a71-11e3-8278-f56d04d293e0
110       unique-uuid=e569a0c9-a650-11e3-942b-f56d04d293e0
111       slave
112       label=""
113       prune-min=00:00:00
114       operating as a SLAVE
115       snapshots directory defaults to /var/hammer/<pfs>
116   Source can update synctid to 0x000000011db6dc20
117
118 - Next, incremental ones:
119   # unxz -c /root/backups/20140308002450_pfs_var.xz | hammer -y mirror-write /pfs/var_2
120   Source can update synctid to 0x000000011db6e440
121
122 - Once done, you can just upgrade the /pfs/var_2
123   # hammer pfs-upgrade /pfs/var_2
124   pfs-upgrade of PFS#10 () succeeded
125
126For the example we used you have to make sure no process is using the current
127/var PFS, and if none is you can just go ahead and unmount it. Afterwards you
128can modify the symbolic link in /pfs to point to the restored one as needed.
129
1304.0 Manipulating dumps
131
132You can upload the .xz files and the .bkp files whenever you want, for example a
133remote FTP server.
134