Messages in this thread | | | Subject | Re: [PATCH 09/14] target/configfs: Expose protection device attributes | From | James Bottomley <> | Date | Mon, 13 Jan 2014 12:24:03 -0800 |
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On Mon, 2014-01-13 at 15:19 -0500, Martin K. Petersen wrote: > >>>>> "nab" == Nicholas A Bellinger <nab@linux-iscsi.org> writes: > > >> What proposed 16 byte scheme? The only DIF proposals I know for > >> SBC-4 are 13-185R0 and 12-369R0 and that's a couple of new algorithms > >> and types because we cannot change the 8 byte PI. > > nab> Then I'm probably getting the SBC version wrong.. It's the one > nab> that includes using CRC32C for the block guard, and larger space > nab> for reference tag as mentioned by MKP. > > This is the Type 4 we have been shopping among various vendors. It > predates and is simpler than HP's proposal (which met resistance in T10 > and was subsequently dropped). So we revived our original Type 4 > proposal which is 16 bytes of protection information per interval > (CRC32C, 48-bit LBA and 6 bytes of app tag). The proposal has been > sitting around for a while waiting for SBC-4 to open.
I'm intrigued by this: how do you get the extra space, since I heard all the drive vendors were adamant that 520 was it for the current manufacturing processes.
James
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