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Diffstat (limited to 'results/classifier/deepseek-2-tmp/output/performance/322602')
| -rw-r--r-- | results/classifier/deepseek-2-tmp/output/performance/322602 | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/results/classifier/deepseek-2-tmp/output/performance/322602 b/results/classifier/deepseek-2-tmp/output/performance/322602 new file mode 100644 index 000000000..bc21babb0 --- /dev/null +++ b/results/classifier/deepseek-2-tmp/output/performance/322602 @@ -0,0 +1,16 @@ + +Snapshot usage makes qcow2 image unusable due to large tables + +To reproduce with 0.9.1 and svn: +- Create a 20G (or some size much greater than system RAM) qcow2 image +- Inside VM, install some OS, formatting whole drive +- Create snapshot with savevm +- Inside VM, reformat and reinstall OS +- Create snapshot with savevm +[...] + +Eventually, qemu crashes, then neither qemu-img nor qemu can open the image because memory is exhausted. The reason is that the whole refcount_table is loaded into memory, and this refcount_table has now become much bigger than the size of memory. + +The refcount_table really needs to be loaded and used in fixed size chunks to avoid this problem. + +Alternatively, there needs to be a way to "rollback" a snapshot without loading the whole disk image normally, so that a snapshot which has made the image unusable in this way can be reversed. \ No newline at end of file |