Re: Sanity check - need a second pair of eyes ;-)

[Eric Sandeen <sandeen@sandeen.net>]

[-- Attachment #1.1: Type: text/plain, Size: 2496 bytes --]

> 
> 
> Hi,
> 
> I'm trying to create an XFS image to be written on a Blue Ray disk, encrypted. I'm told that DVDs have a sector size of 2 KiB, thus it is beter to tell the formatting utility of that, because when creating the image file it is on a hard disk where sector size is 512B.
> 
> Basic procedure:
> 
> truncate -s 50050629632 image_1_50.img
> losetup -f image_1_50.img
> cryptsetup luksFormat --type luks2 --label blueray50img /dev/loop0
> cryptsetup luksOpen /dev/loop0 cr_nombre
> 
> 
> So now I have the image file loop mounted on /dev/mapper/cr_nombre, and I do (this is the step I ask about):
> 
> Telcontar:/home_aux/BLUERAY_OPS # mkfs.xfs -L ANameUnseen -b size=2048 /dev/mapper/cr_nombre
                                                             ^^^ block size

> meta-data=/dev/mapper/cr_nombre  isize=512    agcount=4, agsize=6109184 blks
>          =                       sectsz=512   attr=2, projid32bit=1
>          =                       crc=1        finobt=1, sparse=0, rmapbt=0
>          =                       reflink=0
> data     =                       bsize=2048   blocks=24436736, imaxpct=25
                                   ^^^ block size
>          =                       sunit=0      swidth=0 blks
> naming   =version 2              bsize=4096   ascii-ci=0, ftype=1
> log      =internal log           bsize=2048   blocks=11932, version=2
>          =                       sectsz=512   sunit=0 blks, lazy-count=1
> realtime =none                   extsz=4096   blocks=0, rtextents=0
> Telcontar:/home_aux/BLUERAY_OPS #
> 
> 
> Is that the correct command line to achieve written sectors of 2 KiB?

If you want to set the sector size, the instructions are in the man page for
mkfs.xfs ;)

       -s sector_size
              This  option  specifies  the  fundamental  sector  size  of  the
              filesystem.  The sector_size is specified either as a  value  in
              bytes  with  size=value  or  as  a base two logarithm value with
              log=value.  The default sector_size is 512  bytes.  The  minimum
              value for sector size is 512; the maximum is 32768 (32 KiB). The
              sector_size must be a power of 2 size and cannot be made  larger
              than the filesystem block size.

-Eric

> I ask because I see isize=512 and sectsz=512 and I wonder.
> 
> 
> -- Cheers,
>        Carlos E. R.
>        (from openSUSE 15.0 x86_64 at Telcontar)
> 


[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 873 bytes --]