Re: [libvirt] speeding up qemu core dumps

Eric Blake wrote: > On 08/03/2011 08:37 AM, Jim Fehlig wrote: >> http://lists.nongnu.org/archive/html/qemu-devel/2011-02/msg01156.html >> >> I thought there were more discussions on the topic but can only find the >> above thread ATM. >> >> Do folks here have objections to increasing the migration speed prior to >> core dump? If not, any suggestions for a value? I set the migration >> speed to 1G in doCoreDump() prior to calling qemuMigrationToFile() with >> following improvement dumping a 4G guest > > Why any limit at all? When dumping to file rather than network, I > can't think of any justification for a default limit when targetting a > local drive (a particular installation may have a reasonable limit, > especially if the file involved happens to use a network - think > NFS). It seems like it would make sense to override the qemu defaults > and go with unlimited speed for faster dump and save operations. Agreed, 1G was just a test value, but I'm haven't yet figured out how to define unlimited. From libvirt json monitor connection I tried migrate_set_speed with INT64_MAX, but that was invalid. Using qemu monitor directly, I can go as high as INT64_MAX-512 (qemu) migrate_set_speed 9223372036854775295B (qemu) migrate_set_speed 9223372036854775296B invalid size Any hints on proper way to set unlimited migration speed?