On Mar 10, 2008 15:48 -0700, Klaus Steden wrote: > Is the mmp feature already in the existing Lustre distribution? If so, what > versions are mmp-aware? If not, which version will be the first to > incorporate it?
It's in Lustre 1.6.2+ and 1.4.12, and e2fsprogs-1.40.2+. > On 3/10/08 2:15 PM, "Andreas Dilger" <[EMAIL PROTECTED]>did etch on stone > tablets: > > > On Mar 10, 2008 09:09 -0600, Colin Faber wrote: > >> Is this true even in the case of mounting the OSS as a read only node? > > > > Yes, definitely even a "read only" mount can cause serious corruption. > > There are several issues involved, the most dangerous is that even for > > read-only mounting the journal is replayed by the kernel or otherwise > > the filesystem may appear to be corrupted. > > > > In addition, there is the problem that (meta)data that is cached on the > > read-only mounting node will become incorrect as the writing node is > > changing the filesystem. The ext3 filesystem is not cluster aware. > > > > In order to prevent situations like this, the newer releases of ldiskfs > > and e2fsprogs have an "mmp" (multi-mount protection) feature which will > > prevent the filesystem to be mounted on another node if it is active > > on one node (either mounted, or running e2fsck). > > > > This will be enabled by default on newly-formatted filesystems which > > are created with the "--failover" flag, and can also be enabled by > > hand with "tune2fs -O mmp /dev/XXXX" (replace with MDT or OST device > > names as appropriate). This will prevent the filesystem from being > > mounted or e2fsck'd by old kernels/e2fsprogs so it isn't enabled by > > default on existing filesystems. > > > >> Andreas Dilger wrote: > >>> On Mar 07, 2008 00:04 +0530, Neeladri Bose wrote: > >>> > >>>> To address the performance hit (whatever be the %age) if we setup DRDB in > >>>> active-passive mode across the 4500's but have the LustreFS points to > >>>> separate raid sets from the network across the DRDB pair of 4500's & thus > >>>> become an active-active solution which may actually increase the > >>>> throughput of the LustreFS. > >>>> > >>>> Can it be a possible scenario using DRDB on Linux with ext3 & LustreFS? > >>>> > >>> > >>> No, Lustre does not support active-active export of backing filesystems. > >>> This doesn't work because the backing filesystems (ext3/ZFS) are not > >>> themselves cluster-aware and mounting them on two nodes will quickly > >>> lead to whole filesystem corruption. > > > > Cheers, Andreas > > -- > > Andreas Dilger > > Sr. Staff Engineer, Lustre Group > > Sun Microsystems of Canada, Inc. > > > > _______________________________________________ > > Lustre-discuss mailing list > > [email protected] > > http://lists.lustre.org/mailman/listinfo/lustre-discuss Cheers, Andreas -- Andreas Dilger Sr. Staff Engineer, Lustre Group Sun Microsystems of Canada, Inc. _______________________________________________ Lustre-discuss mailing list [email protected] http://lists.lustre.org/mailman/listinfo/lustre-discuss
