[ ... ] > * leaf nodes composes raid5 arrays from their disks, and > export it as a iSCSI target > * the root node creates a raid5 on top of the exported > targets That's "amazing" to say the least. A way to prove that syntactically valid setups can and do work. I am particularly "amazed" by the idea of using a whole RAID5 subarray just for parity on the top level RAID5. > in this setup i will have to face that an array component > can(and would) grow, [ ... ] This idea seems to me beyond "amazing", and I think that even "stunning" is an understatement. kirk> one more thing: when i first assembled the array with kirk> 4096KB chunks, Indeed, 4MiB chunk sizes are syntactically possible, and it is a rather "exciting" choice, especially for a RAID55. [ ... ] > cryptsetup luksFormat /dev/md0 key || exit 1 Even more "amazing", using 'dm-crypt' over an already "stunning" setup. [ ... ] > mkfs.xfs $FS_DEV Entirely consistently, the syntactically valid setup above is used for a single (presumably very large) filesystem. Very "courageous". Surely there must be extraordinarily good reasons for building a RAID55 with 4MiB chunk (with "amazing" performance for writes, and "stunning" resilience) and with the expectation that one will extend it by growing each subarray, triggering a full two-level reshape every time, and putting 'dm-crypt' and a single filesystem on top of it all. It would be interesting to learn those reasons for people like me whose imagination is limited by stolid pragmatics. -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
