Hi Milan, On Wed, 2010-07-14 at 09:58 +0200, Milan Broz wrote: > On 07/14/2010 12:17 AM, Sven Eschenberg wrote: > > Well, yet it gives me the chance to use the RNG of my choice, might it > > be a HW-RNG in a TPM or chipset, in software of my choice or > > whatsoever ;-). Well, maybe I would want to play with own RNGs and no, I > > am not gonna use any PRNG using linear congruences for that matter :-). > > You can add second keyslot using keyfile and remove former afterwards as workaround. > But if you want to do such low level operations, maybe you want to use dm-crypt > directly, without luks... Yes, since I usually use 2 key slots and 2 keys stored at different locations (since one keystore might get corrupted) I can setup up with some initial passphrase, set the second key to slot 1 and afterwards the primary to slot 0. No worries there - Just saying, it should be fixed whenever possible. > > > Humm, I was just thinking, obviously cryptsetup uses the readahead of > > the device as a measure for alignment. > > No, readahead has nothing to do with device alignment. We are using device topology > as defined by stacking device, this approach is now supported by all > tools (fdisk & partitioning toos, lvm2, mdadm, cryptsetup). > > If topology IOCTLs are not supported (kernels <2.6.32 iirc) it simply defaults > to alignment of 4k. > > MD of course provides proper value according to configured mode (chunks etc). > > Readahead is set the same as underlying device, readahead is dynamic property > of device (you can change it using blockdev --setra anytime) while alignment > is calculated during device format and cannot be changed later.) > > Milan Is there any 'easy' way to access this information. specifically I am interested, why md would report a 6144 sectors alignment on my 4 disk raid5 with 512 kb chunks instead of 3072. Regards -Sven _______________________________________________ dm-crypt mailing list dm-crypt@xxxxxxxx http://www.saout.de/mailman/listinfo/dm-crypt
