Partman manual configuration?

[Peter Smith]

Regarding precise drive formatting, this is also my experince. What i
do is change to another vt and the run fdisk with -H 32 and -S 32,
after this the partitions i create within fdisk will automatically be
aligned to EBS [erase block size], in case of the Intel X25-M this
should be 512 KiB. When this is done i return to the installer and
when partman is loaded, the partitions are already created, no problem
here.

The reason why i want to use another offset for LUKS is primarily because this:

http://www.spinics.net/lists/dm-crypt/msg02421.html

**********
- for cryptetup/LUKS - use "--align-payload" parameter
(default is alignment to 4k boundary, not enough for SSD).
Note that parameter is in 512 bytes sectors!

e.g. you want to align to 4MB boundary ( = 8192 * 512 bytes), use

  cryptsetup luksFormat --align-payload=8192 ...

verify with cryptsetup luksDump (see Payload offset)

(I usually set lvm2 extent size to 4MB and aling LUKS the same,
so the LUKS header takes exactly one extent.)

- and finally, you should optimize FS above that device stack
**********

I must admit that i am VERY in doubt on what to do. If i run the
command "cryptsetup luksDump /dev/sda3" and the LUKS volume sda3 is
created in partman with everything default the offset is "2056" =
(2056 * 512). This is a even multiple of 512 but i do not know if this
is correct or not. I want to ensure the optimal performance and
longevity of the SSD therefore i want to make sure that everything is
correct.

There is no RAID involved as it is a single system disk that i am installing on.

>
> AFAIK, the only way to format a drive precisely is to use fdisk or
> parted in another vt and return to the installer.
>
> I've never used cryptsetup/luksFormat but I couldn't understand from
> your email why you needed to use an offset for them if you'd already
> offset the partition so I looked at the man page.
>
> Both take <device> as an argument so it seems to me that you don't
> need to adjust the alignment after you've done so with fdisk.
>
> Furthermore, the man page also has "--align-payload=value --> Align
> payload at a boundary of value 512-byte sectors. This option is
> relevant for luksFormat. If your block device lives on a RAID it is
> useful to align the filesystem at full stripe boundaries so it can
> take advantage of the RAID's geometry..." which seems to further
> confirm that you can just encrypt your already-properly-aligned
> partition.
>
> --
> ubuntu-users mailing list
> ubuntu-users at lists.ubuntu.com
> Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-users
>