usage pattern: xfsrestore to mirror disks

hi all,

first of all: I am a very happy user of xfs for a long time now. I use xfs in tandem with lvm2 and I have to say I am very pleased.

Now a question:

There are two modes of using xfs(dump,restore): non-cumulative and cumulative. Is this cumulative mode also good to work with full dumps (level0). E.g. the data I have to mirror is not large, and I don't want to rely on inventory data. So I want for instance if between two full dumps a file F was deleted, it should get deleted when I do xfsrestore for the second time.

I don't keep the xfsdump output files but i just apply them via ssh. So something like that would be great!

Maybe someone can shed some light on that.

thanks

--Jakob

Hi Jakob,

The cumulative mode really only relates to restore and not xfsdump. xfsrestore in cumulative mode keeps its version of the directory tree around (restoredir/xfsrestorehousekeepingdir/tree) so that it can use it to compare with and decide if directory entries have been renamed, deleted etc.. The code has been written to do this given an initial level 0 dump and then delta dumps (incremental or resumed). If you try to use a 2nd level 0 dump on restore then it will fail to work - it won't restore anything.
It fails in xfsdump/restore/content.c/dumpcompat() when it compares the restores uuid from persp->a.lastdumpid with the incremental's uuid stored in scrhdrp->cih_last_id (and for a full dump the cih_last_id won't be set).
Unfortunatly, a flag is set in restore so that it stops it from reporting this error (not sure why).
I tried circumventing this uuid check (see the patch) and things seemed to work ok (it did the renames and deletes).
However, I'm uncertain of any other repercussions - it's been a while since I looked at cumulative restores. Maybe others might know.

I wonder if other tools might be useful to you... xfscopy,...?

--Tim

===========================================================================
Index: xfsdump/restore/content.c
===========================================================================

@@ -2019,7 +2019,7 @@ content_stream_restore( ix_t thrdix )
 		} else if ( dumpcompat( resumepr,
 					level,
 					*baseidp,
-					BOOL_FALSE )) {
+					BOOL_TRUE )) {
 			if ( uuid_compare( lastdumprejectedid,
 					 grhdrp->gh_dumpid) == 0) {
 				matchpr = BOOL_FALSE;

@@ -6762,7 +6762,7 @@ dumpcompat( bool_t resumepr, ix_t level,
 						  "selected dump not based on "
 						  "previously applied dump\n"));
 					}
-					return BOOL_FALSE;
+					/*return BOOL_FALSE;*/ return BOOL_TRUE;
 				}
 			}
 		}

Hi Timothy,

thanks for your quick response.
I will apply your patch and try it out.

that would be very interesting for me.

-- Jakob

Hi Jakob,

If I'm understanding your issue correctly, it sounds like rsync would be a good tool for your needs. Or is there some reason you're not using rsync?

Bill