We know MySQL Backups using LVM are pretty cool (check out
mylvmbackup) or MMM though it is quite typical LVM is not
configurable properly to be usable for MySQL Backups.
Quite frequently I find LVM installed on the system but no free
space left to be used as snapshot undo space, which means LVM is
pretty much unusable for backups or required space is very small
- created without good understanding on how much space do you
need for undo.
LVM Snapshot works kind of like Multi Versioning in Innodb - when
you write the new data the new version for the block is stored in
undo space. When snapshot is being read if the block is being
remapped it is read from the undo location.
The LVM Snapshots versioning is however different from database
Multi Versioning because only one old version …
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