On 2017-08-22 16:37:07 [-0600], Chris Murphy wrote: > Documentation says either crc or hash is possible, including crc32. > https://www.kernel.org/doc/Documentation/device-mapper/dm-integrity.txt > > My idea was that if the "normal" path is faulty (and noticed by the crc > > check) it (xfs or the dm layer) would try to read the data via an > > alternative path if possible (say on RAID1/5/6). > > Yes you have to build each layer you want separately with this method. So I tried this: dmsetup create test-raid1 --table '0 4194304 raid raid1 3 0 region_size 1024 2 - /dev/vdc - /dev/vdd' # creating the target (size 1) provided_data_sectors=1 table="0 $provided_data_sectors integrity /dev/mapper/test-raid1 4096 - D 1 internal_hash:crc32c" dmsetup create dm-int --table "$table" dmsetup remove /dev/mapper/dm-int # hexdumped. is there a tool for that? provided_data_sectors=4125208 table="0 $provided_data_sectors integrity /dev/mapper/test-raid1 4096 - D 1 internal_hash:crc32c" dmsetup create dm-int --table "$table" # without that cat, I get checksum errors errors cat < /dev/zero > /dev/mapper/dm-int # mkfs.xfs /dev/mapper/dm-int mount /dev/mapper/dm-int echo asdfghjkl > /mnt/1234567890 umount /mnt/ dmsetup remove /dev/mapper/dm-int dmsetup remove /dev/mapper/dm-raid1 #looking for data hexdump -C /dev/vdc |grep asdfghjkl 01226000 61 73 64 66 67 68 6a 6b 6c 0a 00 00 00 00 00 00 |asdfghjkl.......| echo A > A dd if=A of=/dev/vdc bs=1 seek=19030016 count=1 1+0 records in 1+0 records out 1 byte copied, 0.00152606 s, 0.7 kB/s #check hexdump -C /dev/vdc |grep ^01226000 01226000 41 62 64 66 67 68 6a 6b 6c 0a 00 00 00 00 00 00 |Abdfghjkl.......| #and now dmsetup create test-raid1 --table '0 4194304 raid raid1 3 0 region_size 1024 2 - /dev/vdc - /dev/vdd' table="0 $provided_data_sectors integrity /dev/mapper/test-raid1 4096 - D 1 internal_hash:crc32c" dmsetup create dm-int --table "$table" mount /dev/mapper/dm-int /mnt cat /mnt/1234567890 cat: /mnt/1234567890: Input/output error # and the kernel says dmesg md/raid1:mdX: active with 2 out of 2 mirrors device-mapper: integrity: Checksum failed at sector 0x48 XFS (dm-1): Mounting V5 Filesystem XFS (dm-1): Ending clean mount device-mapper: integrity: Checksum failed at sector 0x48 device-mapper: integrity: Checksum failed at sector 0x48 at some point I expected dm-integrity to check the other disk in RAID. Isn't this possible or is my setup wrong at some point? If it is not possible, could it be made possible? Sebastian -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
