[EMAIL PROTECTED] writes: > Roch - PAE wrote: > > [EMAIL PROTECTED] writes: > > > Jim Mauro wrote: > > > > > > > > Hey Max - Check out the on-disk specification document at > > > > http://opensolaris.org/os/community/zfs/docs/. > > > > > > > > Page 32 illustration shows the rootbp pointing to a dnode_phys_t > > > > object (the first member of a objset_phys_t data structure). > > > > > > > > The source code indicates ub_rootbp is a blkptr_t, which contains > > > > a 3 member array of dva_t 's called blk_dva (blk_dva[3]). > > > > Each dva_t is a 2 member array of 64-bit unsigned ints (dva_word[2]). > > > > > > > > So it looks like each blk_dva contains 3 128-bit DVA's.... > > > > > > > > You probably figured all this out already....did you try using > > > > a objset_phys_t to format the data? > > > > > > > > Thanks, > > > > /jim > > > Ok. I think I know what's wrong. I think the information (most > > likely, > > > a objset_phys_t) is compressed > > > with lzjb compression. Is there a way to turn this entirely off (not > > > just for file data, but for all meta data > > > as well when a pool is created? Or do I need to figure out how to hack > > > in the lzjb_decompress() function in > > > my modified mdb? (Also, I figured out that zdb is already doing the > > > left shift by 9 before dumping DVA values, > > > for anyone following this...). > > > > > > > Max, this might help (zfs_mdcomp_disable) : > > http://www.solarisinternals.com/wiki/index.php/ZFS_Evil_Tuning_Guide#METACOMP > > > Hi Roch, > That would help, except it does not seem to work. I set > zfs_mdcomp_disable to 1 with mdb, > deleted the pool, recreated the pool, and zdb -uuuu still shows the > rootbp in the uberblock_t > to have the lzjb flag turned on. So I then added the variable to > /etc/system, destroyed the pool, > rebooted, recreated the pool, and still the same result. Also, my mdb > shows the same thing > for the uberblock_t rootbp blkptr data. I am running Nevada build 55b. > > I shall update the build I am running soon, but in the meantime I'll > probably write a modified cmd_print() function for my > (modified) mdb to handle (at least) lzjb compressed metadata. Also, I > think the ZFS Evil Tuning Guide should be > modified. It says this can be tuned for Solaris 10 11/06 and snv_52. I > guess that means only those > two releases. snv_55b has the variable, but it doesn't have an effect > (at least on the uberblock_t > rootbp meta-data). > > thanks for your help. > > max >
My bad. The tunable only affects indirect dbufs (so I guess only for large files). As you noted, other metadata is compressed unconditionaly (I guess from the use of ZIO_COMPRESS_LZJB in dmu_objset_open_impl). -r _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
