Re: libparted get_max_geometry problem: additional info

[ben]

*Bump*

Has anyone looked into this? Thank you.



On Wednesday, June 15, 2011 7:04:14 PM ben wrote:
> This is an example of the problem with
> ped_disk_get_max_partition_geometry(). With three partitions I ask
> libparted for a maximum geometry on the last two. In both cases it is
> smaller than it could be by a wide margin.
> 
> 
> **** FDISK OUTPUT ****
> Start: 1951415550
> End  : 1953520064
> 
> Disk /dev/sdc: 1000.2 GB, 1000204886016 bytes
> 255 heads, 63 sectors/track, 121601 cylinders, total 1953525168 sectors
> Units = sectors of 1 * 512 = 512 bytes
> Sector size (logical/physical): 512 bytes / 512 bytes
> I/O size (minimum/optimal): 512 bytes / 512 bytes
> Disk identifier: 0x0000f013
> 
>    Device Boot      Start         End      Blocks   Id  System
> /dev/sdc1            2048     2097215     1047584   83  Linux
> /dev/sdc2      1951422464  1953520063     1048800   83  Linux
> /dev/sdc3      1949317120  1951415548     1049214+  83  Linux
> 
> 
> **** libparted partion layout ****
> 
> Type: 8
> Start: 0
> End:   62
> 
> Type: 4
> Start: 63
> End:   2047
> 
> Type: 0     <-- first partition
> Start: 2048
> End:   2097215
> 
> Type: 4
> Start: 2097216
> End:   1949317119
> 
> Type: 0     <-- second partiton
> Start: 1949317120
> End:   1951415548
> 
> Type: 4
> Start: 1951415549
> End:   1951422463
> 
> Type: 0     <-- third partition
> Start: 1951422464
> End:   1953520063
> 
> Type: 4
> Start: 1953520064
> End:   1953520064
> 
> Type: 8
> Start: 1953520065
> End:   1953525167
> 
> 
> **** results for max geometry -- constraint any ****
> 
> Maximum geometry for 2nd partition
> Start: 2104515
> End  : 1951415549
> 
> The first partition ends at 2097215 but libparted
> puts the start of a maximized partition at 2104515
> which is 7300 sectors or 3.7 megs later.
> 
> 
> 
> Maximum geometry for 3rd partition
> Start: 1951415550
> End  : 1953520064
> 
> Here the beginning is right but the end at 1953520064 is
> short of 1953525167 by 5103 sectors or 2.6 meg.
> 
> 
> **** A different setup ****
> 
> 
> **** FDISK ****
> 
> Disk /dev/sdc: 1000.2 GB, 1000204886016 bytes
> 255 heads, 63 sectors/track, 121601 cylinders, total 1953525168 sectors
> Units = sectors of 1 * 512 = 512 bytes
> Sector size (logical/physical): 512 bytes / 512 bytes
> I/O size (minimum/optimal): 512 bytes / 512 bytes
> Disk identifier: 0x000e6efb
> 
>    Device Boot      Start         End      Blocks   Id  System
> /dev/sdc1       976760832  1953520064   488379616+   5  Extended
> /dev/sdc2            2048   390704370   195351161+  83  Linux
> /dev/sdc3       390717440   402438236     5860398+  83  Linux
> 
> 
> **** liblvm ****
> 
> Start: 0
> End:   62
> 
> Type: 4
> Start: 63
> End:   2047
> 
> Type: 0
> Start: 2048
> End:   390704370
> 
> Type: 4
> Start: 390704371
> End:   390717439
> 
> Type: 0           <--- partition to maximize
> Start: 390717440
> End:   402438236
> 
> Type: 4
> Start: 402438237
> End:   976760831
> 
> Type: 2
> Start: 976760832
> End:   1953520064
> 
> Type: 9
> Start: 976760832
> End:   976760894
> 
> Type: 5
> Start: 976760895
> End:   1953520064
> 
> Type: 8
> Start: 1953520065
> End:   1953525167
> 
> **** results for max geometry -- constraint any ****
> 
> Maximum geometry for partition number 2
> Start: 390716865
> End  : 976751999
> 
> 
> The partition has 13069 sectors or 6.7 megabytes of room
> before the start and yet only gets 575 sectors from libparted.
> After the end it can go to 976760832 but libparted puts
> the end at only 976751999 which is 8833 sectors short or
> 4.5 megs off.
> 
> The results here are with a 1.0 TB drive but small drives can do the
> same. I have actually seen significantly worse rsults but I haven't
> been able to replicate them yet. Thank you for looking into this
> issue.
> 
> _______________________________________________
> bug-parted mailing list
> address@hidden
> https://lists.gnu.org/mailman/listinfo/bug-parted