I was surprised that
xtrabackup supports incremental backups.
xtrabackup copies the data files and understand the format of data files (can have a look inside)? What is a LSN for dummies? I found What is log sequence number ? How it is used in MySQL?.
Quote from Incremental Backup
An incremental backup copies each page whose LSN is newer than the previous incremental or full backup’s LSN. There are two algorithms in use to find the set of such pages to be copied. The first one, available with all the server types and versions, is to check the page LSN directly by reading all the data pages. The second one, available with Percona Server, is to enable the changed page tracking feature on the server, which will note the pages as they are being changed. This information will be then written out in a compact separate so-called bitmap file. The xtrabackup binary will use that file to read only the data pages it needs for the incremental backup, potentially saving many read requests. The latter algorithm is enabled by default if the xtrabackup binary finds the bitmap file. It is possible to specify xtrabackup --incremental-force-scan to read all the pages even if the bitmap data is available.
I still don't understand how this works.
Do you use
xtrabackup Incremental Backup? Do you recommend
xtrabackup Incremental Backup?