diff --git a/sys/dev/vinum/vinum.c b/sys/dev/vinum/vinum.c
index 7149ee862af2..29b7232b8f33 100644
--- a/sys/dev/vinum/vinum.c
+++ b/sys/dev/vinum/vinum.c
@@ -271,6 +271,9 @@ vinumopen(dev_t dev,
     int devminor;					    /* minor number */
 
     devminor = minor(dev);
+    dev->si_bsize_phys = DEV_BSIZE;
+    dev->si_bsize_best = VINUM_BSIZE_BEST;		    /* kludge until we track drive block sizes */
+    dev->si_bsize_max = MAXBSIZE;
     error = 0;
     /* First, decide what we're looking at */
     switch (DEVTYPE(dev)) {
@@ -469,3 +472,6 @@ vinumdump(dev_t dev)
     /* Not implemented. */
     return ENXIO;
 }
+/* Local Variables: */
+/* fill-column: 50 */
+/* End: */
diff --git a/sys/dev/vinum/vinumvar.h b/sys/dev/vinum/vinumvar.h
index a37c9e82d697..9f7c92afcf0e 100644
--- a/sys/dev/vinum/vinumvar.h
+++ b/sys/dev/vinum/vinumvar.h
@@ -178,6 +178,7 @@ enum constants {
     INITIAL_LOCKS = 64,					    /* number of locks to allocate to a plex */
     DEFAULT_REVIVE_BLOCKSIZE = 65536,			    /* size of block to transfer in one op */
     VINUMHOSTNAMELEN = 32,				    /* host name field in label */
+    VINUM_BSIZE_BEST = 4096,				    /* best sector size */
 };
 
 /* device numbers */