sanjaykrk wrote:For Reverse, disadvantage: its slow.
Reverse incremental is slow because raid 5 and spinning disks as said aren't friends with a continuous high random IO workload, however would replace it with raid 0/1/10 with ssds or even better nvme-ssds it would be fast because an enterprise ssd is very capable handling such workload. Lets say the disks Albertwt is using can do 100 IOs (im rounding up) and have perfect schaling the array handles 1200 IOs. One Intel DC P3700 2TB ssd is rated at 450k IOs read / 175k IOs write, even if Veeam is only able to sqeeze a quarter of the rated performance from the P3700 it outperforms the spinning disk array with ease. However most backup budgets doesnt allow to spend a couple grand on a highend enterprise ssd.
Pro: last backup is the full backup, storage use is very stable.
Con: backup is in essence two operations (backup and merge) combined in one operation which tend to be high random IO workload.
Forever forward incremental:
Pro: storage use is stable, backup is usually sequential IO workload, merge happens when backup is done.
con: merge tend to be random IO workload.
Pro: backup is usually sequential IO workload, creating (synthetic) full backups tend to be sequential IO workload, no merge operations.
con: storage use fluctuates based on settings.