[Qemu-devel] [RFC] lively write vmstate with predictable size

[Wenchao Xia <xiawenc@linux.vnet.ibm.com>]

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Hi, Paolo and Juan
    Currently savevm needs pause vm, and I am working on that make it
 lively. Considering the flexibility I'd like to split out the
 functions apart as following:
 1) snapshot lively internal/external
 2) save vmstate lively internal/external
 3) assemble them as will

 1) was sent at
 http://lists.nongnu.org/archive/html/qemu-devel/2012-12/msg02393.html

 but for 2), I think it have problem because file size may grow to a size
 out of control. Considering the migration code, I'd like to propose a
 way to fix it as following:

 Migration logic:
 Src send->dest recv->data analysis->copy data
 Savevm logic:
 Src send->write data to qcow2.

My suggestion:
 Savevm logic:
 Src send->dest recv->data analysis->write data to qcow2/external with
 addr.

   The idea is do the write operation after data analysis, and overwrite
 old data if address overlaps. So this will need qcow2 support
 write snapshot data at "address", and also change some savevm logic.

   Could u give some some comments on this to see if it is workable?


-- 
Best Regards

Wenchao Xia