On 20/mars - 22:50 E.S. Rosenberg wrote: > On Mon, Mar 20, 2017 at 10:19 PM, Dilger, Andreas <[email protected]> > wrote: > > > The underlying "lfs migrate" command (not the "lfs_migrate" script) in > > newer Lustre versions (2.9) is capable of migrating files that are in use > > by using the "--block" option, which prevents other processes from > > accessing or modifying the file during migration. > > > > Unfortunately, "lfs_migrate" doesn't pass that argument on, though it > > wouldn't be hard to change the script. Ideally, the "lfs_migrate" script > > would pass all unknown options to "lfs migrate". > > > > > > The other item of note is that setting the OST inactive on the MDS will > > prevent the MDS from deleting objects on the OST (see > > https://jira.hpdd.intel.com/browse/LU-4825 for details). In Lustre 2.9 > > and later it is possible to set on the MDS: > > > > mds# lctl set_param osp.<OST>.create_count=0 > > > > to stop MDS allocation of new objects on that OST. On older versions it is > > possible to set on the OSS: > > > > oss# lctl set_param obdfilter.<OST>.degraded=1 > > > > so that it tells the MDS to avoid it if possible, but this isn't a hard > > exclusion. > > > > It is also possible to use a testing hack to mark an OST as out of inodes, > > but that only works for one OST per OSS and it sounds like that won't be > > useful in this case. > > > > Cheers, Andreas > > > You're making me want Lustre 2.9 more :) but for now I'm still stuck on 2.8 > and because this is very much production these days I'm more careful with > the update (hoping to finally get hw allocated for a test env soon to test > the update). > Thanks, > Eli >
Hello, this safer version of `lfs migrate' (LU-4840) is actually available in 2.8. When used with --non-block flag, a concurrent open of the file being migrated will cause the migration to fail. With --block (or nothing, it's the default behavior) and as Andreas said, concurrent opens will block until the migration completes. Regards -- Henri Doreau _______________________________________________ lustre-discuss mailing list [email protected] http://lists.lustre.org/listinfo.cgi/lustre-discuss-lustre.org
