Hi, Andrew M.A. Cater wrote: > > Write only storage - DVD-R or equivalent Blu-Ray
Tim Woodall wrote: > I already do that but currently that means I have roughly one month of > backups on network accessible storage before I write to disc. I do a daily incremental backup on BD-R (plus three on BD-RE and one on DVD+RW). All my burners can write at least 128 sessions to BD-R. My ASUS BW-16D1HT does more than 230. I hope to reach a new record in a few weeks with my current 11 o'clock BD-R: Drive type : vendor 'ASUS' product 'BW-16D1HT' revision '1.01' ... Media current: BD-R sequential recording Media product: CMCMAG/BA5/0 , CMC Magnetics Corporation Media status : is written , is appendable Media blocks : 8843072 readable , 3376320 writable , 12219392 overall ISO offers : Rock_Ridge ISO loaded : Rock_Ridge TOC layout : Idx , sbsector , Size , Volume Id ISO session : 1 , 0 , 1992263s , HOME_2021_03_02_110936 ISO session : 2 , 1992416 , 33546s , HOME_2021_03_03_110514 ISO session : 3 , 2026112 , 34060s , HOME_2021_03_04_111021 ... ISO session : 203 , 8802368 , 19349s , HOME_2021_09_20_121951 ISO session : 204 , 8821888 , 21020s , HOME_2021_09_21_123308 Media summary: 204 sessions, 8843072 data blocks, 16.9g data, 6594m free The backup is done essentially according to man xorriso example "Incremental backup of a few directory trees" with more -update_r commands and some -not_paths commands. Linux mounts by default the youngest state. But by help of mount(8) option -o sbsector= and the numbers in the "sbsector" column it is possible to mount older states. (With -o loop you may even mount more than one and compare them.) DVD+R can take 153 sessions. DVD-R can theoretically take 99 sessions, but there is substantial waste space between them. So many sessions means few payload. Have a nice day :) Thomas