On 07/24/2018 06:20 PM, Eric Blake wrote:
On 07/24/2018 07:17 AM, Leonid Bloch wrote:
Signed-off-by: Leonid Bloch [1]<lbl...@janustech.com>
---
docs/qcow2-cache.txt | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/docs/qcow2-cache.txt b/docs/qcow2-cache.txt
index 8a09a5cc5f..a0a1267482 100644
--- a/docs/qcow2-cache.txt
+++ b/docs/qcow2-cache.txt
@@ -97,9 +97,9 @@ need:
l2_cache_size = disk_size_GB * 131072
refcount_cache_size = disk_size_GB * 32768
-QEMU has a default L2 cache of 1MB (1048576 bytes) and a refcount
-cache of 256KB (262144 bytes), so using the formulas we've just
seen
-we have
+QEMU has a default L2 cache of 1MB (1048576 bytes) or 8 clusters
(whichever
+is larger) and a refcount cache of 256KB (262144 bytes), so using
the
Looks suspicious; isn't the refcount cache size also dependent on
the cluster size?
Yes, it's 4*cluster_size. But I realize now that the text here speaks
about the default sizes, which means with with 64KB clusters. So this
fix is not necessary. Will drop this patch.
+formulas we've just seen we have (assuming the L2 cache is 1MB):
1048576 / 131072 = 8 GB of virtual disk covered by that cache
262144 / 32768 = 8 GB
References
1. mailto:lbl...@janustech.com
