1DUMP(8) 386BSD System Manager's Manual DUMP(8) 2 3NNAAMMEE 4 dduummpp - filesystem backup 5 6SSYYNNOOPPSSIISS 7 dduummpp [00112233445566778899ffuussddWWnn [_a_r_g_u_m_e_n_t ...]] [_f_i_l_e_s_y_s_t_e_m] 8 9DDEESSCCRRIIPPTTIIOONN 10 DDuummpp examines files on a filesystem and determines which files need to be 11 backed up. These files are copied to the given disk, tape or other 12 storage medium for safe keeping (see rdump(8) for remote backups) . A 13 dump that is larger than the output medium is broken into multiple 14 volumes of a fixed size; the actual size is determined by the tape size 15 and density and/or block count options below. By default, the same 16 output file name is used for each volume after prompting the operator to 17 change media. 18 19 The following options are supported by dduummpp:: 20 21 00--99 Dump levels. A level 0, full backup, guarantees the entire file 22 system is copied. A level number above 0, incremental backup, 23 tells dump to copy all files new or modified since the last dump of 24 the same or lower level. The default level is 9. 25 26 ff [_f_i_l_e] 27 Write the backup to _f_i_l_e; _f_i_l_e may be a special device file like 28 /_d_e_v/_r_m_t_1_2 (a tape drive), /_d_e_v/_r_s_d_1_c (an optical drive), an 29 ordinary file, or `--' (the standard output). Multiple file names 30 may be given as a single argument separated by commas. Each file 31 will be used for one dump volume in the order listed; if the dump 32 requires more volumes than the number of names given, the last file 33 name will used for all remaining volumes after prompting for media 34 changes. 35 36 dd _d_e_n_s_i_t_y 37 Set tape density to _d_e_n_s_i_t_y. The default is 1600BPI. 38 39 nn Whenever dduummpp requires operator attention, notify all operators in 40 the group ``operator'' by means similar to a wall(1). 41 42 ss _f_e_e_t 43 Attempt to caluculate the amount of tape needed at a particular 44 density. If this amount is exceeded, dduummpp prompts for a new tape. 45 It is recommended to be a bit conservative on this option. The 46 default tape length is 2300 feet. 47 48 BB _b_l_o_c_k_s 49 Set the size of the dump file to the specified number of 1024-byte 50 blocks, superceding the tape size and density. 51 52 uu Update the file /_e_t_c/_d_u_m_p_d_a_t_e_s after a successful dump. The format 53 of /_e_t_c/_d_u_m_p_d_a_t_e_s is readable by people, consisting of one free 54 format record per line: filesystem name, increment level and 55 ctime(3) format dump date. There may be only one entry per 56 filesystem at each level. The file /_e_t_c/_d_u_m_p_d_a_t_e_s may be edited to 57 change any of the fields, if necessary. 58 59 WW DDuummpp tells the operator what file systems need to be dumped. This 60 information is gleaned from the files /_e_t_c/_d_u_m_p_d_a_t_e_s and 61 /_e_t_c/_f_s_t_a_b. The WW option causes dduummpp to print out, for each file 62 system in /_e_t_c/_d_u_m_p_d_a_t_e_s the most recent dump date and level, and 63 highlights those file systems that should be dumped. If the WW 64 option is set, all other options are ignored, and dduummpp exits 65 66 immediately. 67 68 ww Is like W, but prints only those filesystems which need to be 69 dumped. 70 71 DDuummpp requires operator intervention on these conditions: end of tape, end 72 of dump, tape write error, tape open error or disk read error (if there 73 are more than a threshold of 32). In addition to alerting all operators 74 implied by the nn key, dduummpp interacts with the operator on _d_u_m_p'_s control 75 terminal at times when dduummpp can no longer proceed, or if something is 76 grossly wrong. All questions dduummpp poses _m_u_s_t be answered by typing yes 77 or no, appropriately. 78 79 Since making a dump involves a lot of time and effort for full dumps, 80 dduummpp checkpoints itself at the start of each tape volume. If writing 81 that volume fails for some reason, dduummpp will, with operator permission, 82 restart itself from the checkpoint after the old tape has been rewound 83 and removed, and a new tape has been mounted. 84 85 DDuummpp tells the operator what is going on at periodic intervals, including 86 usually low estimates of the number of blocks to write, the number of 87 tapes it will take, the time to completion, and the time to the tape 88 change. The output is verbose, so that others know that the terminal 89 controlling dduummpp is busy, and will be for some time. 90 91 In the event of a catastrophic disk event, the time required to restore 92 all the necessary backup tapes or files to disk can be kept to a minimum 93 by staggering the incremental dumps. An efficient method of staggering 94 incremental dumps to minimize the number of tapes follows: 95 96 oo Always start with a level 0 backup, for example: 97 98 /etc/dump 0ufds /dev/nrst1 54000 6000 /usr/src 99 100 This should be done at set intervals, say once a month or once 101 every two months, and on a set of fresh tapes that is saved 102 forever. 103 104 oo After a level 0, dumps of active file systems are taken on a 105 daily basis, using a modified Tower of Hanoi algorithm, with 106 this sequence of dump levels: 107 108 3 2 5 4 7 6 9 8 9 9 ... 109 110 For the daily dumps, it should be possible to use a fixed 111 number of tapes for each day, used on a weekly basis. Each 112 week, a level 1 dump is taken, and the daily Hanoi sequence 113 repeats beginning with 3. For weekly dumps, another fixed set 114 of tapes per dumped file system is used, also on a cyclical 115 basis. 116 117 After several months or so, the daily and weekly tapes should get rotated 118 out of the dump cycle and fresh tapes brought in. 119 120FFIILLEESS 121 /dev/rrp1g default filesystem to dump from (system dependent). 122 /dev/rmt8 default tape unit to dump to 123 /etc/dumpdates new format dump date record 124 /etc/fstab dump table: file systems and frequency 125 /etc/group to find group _o_p_e_r_a_t_o_r 126 127SSEEEE AALLSSOO 128 rdump(8), restore(8), dump(5), fstab(5) 129 130DDIIAAGGNNOOSSTTIICCSS 131 Many, and verbose. 132 133 Dump exits with zero status on success. Startup errors are indicated 134 with an exit code of 1; abnormal termination is indicated with an exit 135 code of 3. 136 137BBUUGGSS 138 Fewer than 32 read errors on the filesystem are ignored. Each reel 139 requires a new process, so parent processes for reels already written 140 just hang around until the entire tape is written. 141 142 DDuummpp with the WW or ww options does not report filesystems that have never 143 been recorded in /_e_t_c/_d_u_m_p_d_a_t_e_s, even if listed in /_e_t_c/_f_s_t_a_b. 144 145 It would be nice if dduummpp knew about the dump sequence, kept track of the 146 tapes scribbled on, told the operator which tape to mount when, and 147 provided more assistance for the operator running restore. 148 149HHIISSTTOORRYY 150 A dduummpp command appeared in Version 6 AT&T UNIX. 151 1524th Berkeley Distribution June 17, 1991 3 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199