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 > > On Mar 20, 2017, at 13:11, Brett Lee <[email protected]> wrote: > > Hi Eli, > > I believe that is still the case with lfs_migrate. If otherwise, we'll > probably hear soon. > > You should be able to disable those OSTs while keeping the file system > active - via a command on the MDS(s) as well as the clients. My notes have > the command as shown below, but please confirm via the appropriate Lustre > manual: > > lctl set_param osc.<fsname>-<OST00xy>-*.active=0 > > Brett > -- > Protect Yourself Against Cybercrime > PDS Software Solutions LLC > https://www.TrustPDS.com <https://www.trustpds.com/> > > On Mon, Mar 20, 2017 at 10:43 AM, E.S. Rosenberg < > [email protected]> wrote: > >> In the man page it says the following: >> >> Because lfs_migrate is not yet closely integrated with the MDS, it >> cannot determine whether a file is currently open and/or in-use by other >> applications or nodes. That makes it UNSAFE for use on files that might be >> modified by other applications, since the migrated file is only a copy of >> the current file, and this will result in the old file becoming an >> open-unlinked file and any modifications to that file will be lost. >> >> Is this still the case? >> Is there a better way to disable OSTs while keeping the filesystem live? >> >> Background: >> We need to take a OSS enclosure that hosts multiple OSTs offline for >> hardware maintenance, I'd like to do this without bringing Lustre as a >> whole down. I made sure there is enough space on the other OSTs to house >> the contents of the machine going offline and am now about to move things. >> >> Thanks, >> Eli >> >> _______________________________________________ >> lustre-discuss mailing list >> [email protected] >> http://lists.lustre.org/listinfo.cgi/lustre-discuss-lustre.org >> >> > _______________________________________________ > lustre-discuss mailing list > [email protected] > http://lists.lustre.org/listinfo.cgi/lustre-discuss-lustre.org > >
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