On Fri, Aug 25, 2023 at 13:52:14 +0200, Kristina Hanicova wrote:
This introduces the ability to set the discard granularity option
for a disk. It defines the smallest amount of data that can be
discarded in a single operation (useful for managing and
optimizing storage).
Signed-off-by: Kristina Hanicova <khanicov(a)redhat.com>
---
docs/formatdomain.rst | 6 +++++-
src/conf/domain_conf.c | 19 ++++++++++++++++++-
src/conf/domain_conf.h | 1 +
src/conf/domain_validate.c | 3 ++-
src/conf/schemas/domaincommon.rng | 5 +++++
src/qemu/qemu_domain.c | 2 ++
6 files changed, 33 insertions(+), 3 deletions(-)
diff --git a/docs/formatdomain.rst b/docs/formatdomain.rst
index cd9cb02bf8..0d0812f08c 100644
--- a/docs/formatdomain.rst
+++ b/docs/formatdomain.rst
@@ -2588,7 +2588,7 @@ paravirtualized driver is specified via the ``disk`` element.
<driver name='qemu' type='raw'/>
<source dev='/dev/sda'/>
<geometry cyls='16383' heads='16' secs='63'
trans='lba'/>
- <blockio logical_block_size='512'
physical_block_size='4096'/>
+ <blockio logical_block_size='512' physical_block_size='4096'
discard_granularity='4096'/>
<target dev='hdj' bus='ide'/>
</disk>
<disk type='volume' device='disk'>
@@ -3435,6 +3435,10 @@ paravirtualized driver is specified via the ``disk`` element.
this would be the value returned by the BLKPBSZGET ioctl and describes the
disk's hardware sector size which can be relevant for the alignment of
disk data.
+ ``discard_granularity``
+ The smallest amount of data that can be discarded in a single operation.
+ It impacts the unmap operations and it must be a multiple of a
+ ``logical_block_size``.
Add a note that most hypervisors select the proper setting and users
don't really need to tweak this.
Reviewed-by: Peter Krempa <pkrempa(a)redhat.com>