Commit Graph

7 Commits

Author SHA1 Message Date
Peter Krempa
c014e11191 kbase: incrementalbackupinternals: Describe 'block commit'
oVirt does merge images out of libvirt in some cases. Add docs outlining
how it's done from a high level.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
2020-06-25 12:24:01 +02:00
Peter Krempa
4d064f9787 kbase: incrementalbackupinternals: Replace bash with pseudocode
Simplify the docs and reduce maintenance burden by just describing the
algorithm by a pseudo-language. Users are encouraged to use libvirt
anyways and projects such as oVirt which do some management of storage
themselves are unlikely to use bash anyways.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
2020-06-25 12:21:13 +02:00
Peter Krempa
abf20e65f7 kbase: incrementalbackupinternals: Add section on 'qemu-img bitmap' use
Define what users should look for when wanting to manipulate bitmaps
themselves.

Later on a patch will turn the bash algorithms into pseudocode for
simplicity.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
2020-06-25 12:21:13 +02:00
Peter Krempa
a4e81e0c32 kbase: incrementalbackupinternals: Add secion on bitmap handling in shell
Add a section that outlines usage of tools to handle bitmaps and
introduce terms corresponding to the output of qemu-img to be used in
further sections.

With this we can simplify the section about checking bitmap health as we
don't have to explain the qemu-img output but can refer to the newly
defined terms.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
2020-06-25 12:21:13 +02:00
Peter Krempa
de56070c9d kbase: incrementalbackupinternals: Clarify language in snapshots section
Emphasize what needs to happen and also that creating a snapshot doesn't
create the appropriate bitmaps. Also mention that granularity is kept.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
2020-06-25 12:21:13 +02:00
Peter Krempa
19061038a7 kbase: incrementalbackupinternals: Add snapshot terminology
Make it obvious what's meant by 'overlay' and 'backing image' for sake
of extension of the document.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
2020-06-25 12:21:13 +02:00
Peter Krempa
da5e5a1e15 kbase: Add document outlining internals of incremental backup in qemu
Outline the basics and how to integrate with externally created
overlays. Other topics will continue later.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
2020-06-22 16:11:00 +02:00