SSD support in Anaconda/F14

[Roberto Ragusa]

Camilo Mesias wrote:
>
> The output of sfdisk -l doesn't make it obvious if the disk is using
> 4k sectors or is aligned in any particular way.
[...]
> 
> Disk /dev/sda: 7297 cylinders, 255 heads, 63 sectors/track
> Units = cylinders of 8225280 bytes, blocks of 1024 bytes, counting from 0
> 
>    Device Boot Start     End   #cyls    #blocks   Id  System
> /dev/sda1   *      0+     63-     64-    512000   83  Linux
> /dev/sda2         63+   7297-   7234-  58101760   8e  Linux LVM
> /dev/sda3          0       -       0          0    0  Empty
> /dev/sda4          0       -       0          0    0  Empty

IMHO it makes obvious that it is extremely bad aligned.
C/H/S are all odd numbers (that is, not even).
The important partition (sda2) starts at 63, which is off alignment.

I don't know if your drive is one of the "let's shift every sector by one
to make MSDOS..WINXP aligned". If the SSD is not doing tricks,
this layout is misaligned.

I partitioned my SSD in the following way.
I forced 56 as sector/track (which is dividable by 8, 4096/512), so
all partitions should come out 4KiB aligned.
(used both CHS and sector output for clarity)

No guarantee that my approach is right and that your SSD is wrong. :-)

# fdisk -l /dev/sda

Disk /dev/sda: 256.0 GB, 256060514304 bytes
54 heads, 56 sectors/track, 165383 cylinders
Units = cylinders of 3024 * 512 = 1548288 bytes
Disk identifier: 0x180397b2

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1           1        1484   83  Linux
/dev/sda2               2      165383   250057584    5  Extended
/dev/sda5               2         476      718172   83  Linux
/dev/sda6             477       38620    57673700   83  Linux
/dev/sda7           38621       42782     6292916   82  Linux swap / Solaris
/dev/sda8           42783       98263    83887244   83  Linux
/dev/sda9           98264      165383   101485412   83  Linux

# fdisk -l -u /dev/sda

Disk /dev/sda: 256.0 GB, 256060514304 bytes
54 heads, 56 sectors/track, 165383 cylinders, total 500118192 sectors
Units = sectors of 1 * 512 = 512 bytes
Disk identifier: 0x180397b2

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *          56        3023        1484   83  Linux
/dev/sda2            3024   500118191   250057584    5  Extended
/dev/sda5            3080     1439423      718172   83  Linux
/dev/sda6         1439480   116786879    57673700   83  Linux
/dev/sda7       116786936   129372767     6292916   82  Linux swap / Solaris
/dev/sda8       129372824   297147311    83887244   83  Linux
/dev/sda9       297147368   500118191   101485412   83  Linux

-- 
   Roberto Ragusa    mail at robertoragusa.it