Hi! I used to use the FreeBSD on i386 architecture together with the controller Mylex AcceleRAID 170.There was RAID 0+1 configured on it out of 5 discs (Enhanced Mirroring). # pciconf -lvc ... mly0@pci0:6:1:0: class=0x010400 card=0x00521069 chip=0x00501069 rev=0x02 hdr=0x00 vendor = 'Mylex Corp' device = 'AcceleRAID Disk Array' class = mass storage subclass = RAID cap 01[80] = powerspec 2 supports D0 D3 current D0 I used this configuration on i386 architecture with the following versions FreeBSD: 4.x, 5.x, 6.x and 7.0. It always worked perfectly. But recently I got needed 8 GB RAM so I had to install the version FreeBSD for AMD64. First I tried the 7.0, and after all - RELENG_7_1 dated 12.12.2008. Both these systems work with the files system located on RAID unstabl?! Meanwhile the same hardware on i386 architecture works with RELENG_7_1 perfectly. Hardware: MB INTEL DG33FB, CPU Intel(R) Core(TM)2 Quad CPU @ 2.40 GHz, RAM 8 GB. The base system is installed on a separate IDE disc. # df -h Filesystem Size Used Avail Capacity Mounted on /dev/ad4s1a 496M 111M 345M 24% / devfs 1.0K 1.0K 0B 100% /dev /dev/ad4s1d 3.9G 22K 3.6G 0% /tmp /dev/ad4s1f 333G 52G 255G 17% /usr /dev/ad4s1e 15G 41M 14G 0% /var /dev/da0s1d 70.7G 410K 70.1G 0% /mnt/da0/d I carried out the following test by creating 3 big sized files of 1 GB each, and then deleting them: # cd /mnt/da0/d # dd if=/dev/zero of=test1 bs=1024k count=1024 # dd if=/dev/zero of=test2 bs=1024k count=1024 # dd if=/dev/zero of=test5 bs=1024k count=1024 # rm test* After that I tried to unmount the files system, but I get a message of the kernel panic: # cd / # umount /mnt/da0/d ... bad block 123456789, ino 176 dev = da0s1d, block = 4, fs = /mnt/da0/d panic: ffs_blkfree: freeing free block cpuid = 3 Uptime: 34 min... The test was successful when using the i386 architecture with the same hardware Taking a piece of advice of my friend, I used a dirty patch: === [code] ==diff -Nru src.orig/sys/cam/scsi/scsi_da.c src/sys/cam/scsi/scsi_da.c --- src.orig/sys/cam/scsi/scsi_da.c 2008-12-10 10:01:40.000000000 +0800 +++ src/sys/cam/scsi/scsi_da.c 2008-12-19 12:18:27.000000000 +0800 @@ -1187,7 +1187,7 @@ if (match != NULL) softc->quirks = ((struct da_quirk_entry *)match)->quirks; else - softc->quirks = DA_Q_NONE; + softc->quirks = DA_Q_NO_SYNC_CACHE; // Dirty hack for AMD64 /* Check if the SIM does not want 6 byte commands */ xpt_setup_ccb(&cpi.ccb_h, periph->path, /*priority*/1); === [/code] == This patch solved the problem and the systems stopped being panicking. But I assume that this solution is wrong as the hardware works on i386 architecture without this patch well.