On Wednesday November 20, sdake@mvista.com wrote: > Neil, > > I would suggest adding a 64 bit field called "unique_identifier" to the > per-device structure. This would allow a RAID volume to be locked to a > specific host, allowing the ability for true multihost operation. You seem to want a uniq id in 'per device' which will identify the 'volume'. That doesn't make sense to me so maybe I am missing something. If you want to identify the 'volume', you put some sort of id in the 'per-volume' data structure. This is what the 'name' field is for. > > For FibreChannel, we have a patch which places the host's FC WWN into > the superblock structure, and only allows importing an array disk (via > ioctl or autostart) if the superblock's WWN matches the target dev_t's > host fibrechannel WWN. We also use this for environments where slots > are used to house either CPU or disks and lock a RAID array to a > specific cpu slot. WWNs are 64 bit, which is why I suggest such a large > bitsize for this field. This really helps in hotswap environments where > a CPU blade is replaced and should use the same disk, but the disk > naming may have changed between reboots. > > This could be done without this field, but then the RAID arrays could be > started unintentionally by the wrong host. Imagine a host starting the > wrong RAID array while it has been already started by some other party > (forcing a rebuild) ugh! Put your 64 bit WWN in the 'name' field, and teach user-space to match 'name' to FC adapter. Does that work for you? NeilBrown - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
