diff -urN lvm-ref/drivers/md/lvm.c lvm/drivers/md/lvm.c
--- lvm-ref/drivers/md/lvm.c	Sun Nov 18 06:09:43 2001
+++ lvm/drivers/md/lvm.c	Sun Nov 18 06:10:04 2001
@@ -259,9 +259,13 @@
 
 #include "lvm-internal.h"
 
-#define	LVM_CORRECT_READ_AHEAD( a) \
-   if      ( a < LVM_MIN_READ_AHEAD || \
-             a > LVM_MAX_READ_AHEAD) a = LVM_MAX_READ_AHEAD;
+#define	LVM_CORRECT_READ_AHEAD(a)		\
+do {						\
+	if ((a) < LVM_MIN_READ_AHEAD ||		\
+	    (a) > LVM_MAX_READ_AHEAD)		\
+		(a) = LVM_DEFAULT_READ_AHEAD;	\
+	read_ahead[MAJOR_NR] = (a);		\
+} while(0)
 
 #ifndef WRITEA
 #  define WRITEA WRITE
@@ -935,6 +944,7 @@
 		    (long) arg > LVM_MAX_READ_AHEAD)
 			return -EINVAL;
 		lv_ptr->lv_read_ahead = (long) arg;
+		read_ahead[MAJOR_NR] = lv_ptr->lv_read_ahead;
 		break;
 
 
diff -urN lvm-ref/include/linux/lvm.h lvm/include/linux/lvm.h
--- lvm-ref/include/linux/lvm.h	Sun Nov 18 06:09:43 2001
+++ lvm/include/linux/lvm.h	Sun Nov 18 06:10:04 2001
@@ -259,8 +259,9 @@
 #define	LVM_MAX_STRIPES		128	/* max # of stripes */
 #define	LVM_MAX_SIZE            ( 1024LU * 1024 / SECTOR_SIZE * 1024 * 1024)	/* 1TB[sectors] */
 #define	LVM_MAX_MIRRORS    	2	/* future use */
-#define	LVM_MIN_READ_AHEAD	2	/* minimum read ahead sectors */
-#define	LVM_MAX_READ_AHEAD	120	/* maximum read ahead sectors */
+#define	LVM_MIN_READ_AHEAD	0	/* minimum read ahead sectors */
+#define	LVM_DEFAULT_READ_AHEAD	1024	/* default read ahead sectors for 512k scsi segments */
+#define	LVM_MAX_READ_AHEAD	10000	/* maximum read ahead sectors */
 #define	LVM_MAX_LV_IO_TIMEOUT	60	/* seconds I/O timeout (future use) */
 #define	LVM_PARTITION           0xfe	/* LVM partition id */
 #define	LVM_NEW_PARTITION       0x8e	/* new LVM partition id (10/09/1999) */