21 Sep
2008
21 Sep
'08
7:53 p.m.
Kay Diederichs wrote:
BTW, there is - even with current kernels - no speed gain in using RAID1 - see http://kernelnewbies.org/KernelProjects/Raid1ReadBalancing .
except, thats wrong. I unwrapped a recent kernel source tarball from kernel.org and found...
static struct mirror *choose_mirror(struct mirror_set *ms, sector_t sector) { struct mirror *m = get_default_mirror(ms);
do { if (likely(!atomic_read(&m->error_count))) return m;
if (m-- == ms->mirror) m += ms->nr_mirrors; } while (m != get_default_mirror(ms));
return NULL; }
so it appears its a round robin ...