Re: [dm-devel] Help request: setting up /dev/zero using dm-crypt ...
On 02/07/2018 09:50 AM, Ravi Prakash Putchala wrote: Thank you, Milan. Will try these. If you need experiment over a memory device, use either ramdisk, scsi_debug module to it. Another alternative is to create dm-zero device and use plain dm-crypt (not LUKS). create dm-zero device: How do I do this? Sorry, I do not have much expertise in Linux. E.g. 10TiB "zero" mapped device (pick your name instead of 'z'): dmsetup create z --table "0 $((10*1024*1024*1024*2)) zero" Block device node for this is: /dev/mapper/z See dmsetup(8) and device-mapper target documentation in kernel source, for instance Documentaion/device-mapper/zero.txt. Heinz Ravi -- dm-devel mailing list dm-devel@redhat.com https://www.redhat.com/mailman/listinfo/dm-devel -- dm-devel mailing list dm-devel@redhat.com https://www.redhat.com/mailman/listinfo/dm-devel
Re: [dm-devel] Help request: setting up /dev/zero using dm-crypt ...
Thank you, Milan. Will try these. If you need experiment over a memory device, use either ramdisk, scsi_debug > module to it. > Another alternative is to create dm-zero device and use plain dm-crypt > (not LUKS). > create dm-zero device: How do I do this? Sorry, I do not have much expertise in Linux. Ravi -- dm-devel mailing list dm-devel@redhat.com https://www.redhat.com/mailman/listinfo/dm-devel
Re: [dm-devel] Help request: setting up /dev/zero using dm-crypt ...
On 02/07/2018 09:15 AM, Ravi Prakash Putchala wrote: > We would like to experiment and see the performance results with different > options of dm-crypt. To do this we would like to setup /dev/zero with > dm-crypt as mentioned in > https://www.redhat.com/archives/dm-devel/2015-February/msg00106.html > However, when I did the following no new mapping gets created in /dev/mapper: > > # cryptsetup -y luksFormat /dev/zero This command cannot work, /dev/zero is a character device, moreover all writes there are discarded. Seems cryptsetup does not print error message here (that is a bug) but return value of this command indicates the problem: 4 - that means "wrong device specified" (see man page). If you need experiment over a memory device, use either ramdisk, scsi_debug module to it. Another alternative is to create dm-zero device and use plain dm-crypt (not LUKS). Milan -- dm-devel mailing list dm-devel@redhat.com https://www.redhat.com/mailman/listinfo/dm-devel
[dm-devel] Help request: setting up /dev/zero using dm-crypt ...
Hi, We would like to experiment and see the performance results with different options of dm-crypt. To do this we would like to setup /dev/zero with dm-crypt as mentioned in https://www.redhat.com/archives/dm-devel/2015-February/msg00106.html However, when I did the following no new mapping gets created in /dev/mapper: # cryptsetup -y luksFormat /dev/zero # cryptsetup luksOpen /dev/zero dm-zero # cryptsetup status /dev/mapper/dm-zero /dev/mapper/dm-zero is inactive. Could you please help by giving instructions on how to do this right? Thank you. Ravi -- dm-devel mailing list dm-devel@redhat.com https://www.redhat.com/mailman/listinfo/dm-devel
