On 09/10/2017 09:43 PM, Sebastian Andrzej Siewior wrote: > 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? There is integritysetup tool (part of cryptsetup package) that automates format and mount of dm-integrity devices. For now in devel git, I expect we will do some release package this month. (So no need to use dmsetup here.) ... > at some point I expected dm-integrity to check the other disk in RAID. The dm-integrity has no connection to RAID, it will just return EILSEQ (instead of EIO error) to inform that the error is an data integrity error, not a media (or other) IO error. > Isn't this possible or is my setup wrong at some point? If it is not > possible, could it be made possible? It is up to RAID driver to handle integrity error properly (the same should happen for hardware DIF integrity error I guess - you can try to simulate it with scsi_debug). Milan -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
