Re: fdisk on centos 6

Steve Clark <sclark@xxxxxxxxxxxxx> · Fri, 16 Sep 2011 08:37:55 -0400

    On 09/16/2011 08:10 AM, Jerry Geis wrote:

      On 09/16/2011 06:59 AM, Steve Clark wrote:

        On 09/15/2011 06:03 PM, Jerry Geis wrote:

            I think the fdisk in 6 tries to align on 4k boundaries. Does fdisk -c do the
same thing?

          Scott - thanks I just tried -cu and same result.

jerry

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        have you tried sfdisk?

      Steve - I had not - but asking sfdisk to list the device on centos has 
the wrong geometry to start
with just like fdisk does. it should be 255 heads and 63 sectors.

sfdisk -v
sfdisk (util-linux-ng 2.17.2)

  sfdisk -l /dev/sde

Disk /dev/sde: 1022 cylinders, 247 heads, 62 sectors/track
Warning: The partition table looks like it was made
   for C/H/S=*/255/63 (instead of 1022/247/62).
For this listing I'll assume that geometry.
Units = cylinders of 8225280 bytes, blocks of 1024 bytes, counting from 0

    Device Boot Start     End   #cyls    #blocks   Id  System
/dev/sde1   *      0+    974-    975-   7830616+   b  W95 FAT32
         end: (c,h,s) expected (974,221,63) found (1023,254,63)
/dev/sde2          0       -       0          0    0  Empty
/dev/sde3          0       -       0          0    0  Empty
/dev/sde4          0       -       0          0    0  Empty

----------------
This is centos 5
sfdisk -v
sfdisk (util-linux 2.13-pre7)

  sfdisk -l /dev/sdb

Disk /dev/sdb: 974 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/sdb1   *      0+    851     852-   6843658+  83  Linux
/dev/sdb2        852     973     122     979965   82  Linux swap / Solaris
/dev/sdb3          0       -       0          0    0  Empty
/dev/sdb4          0       -       0          0    0  Empty

    Hmm...

      I have an automated script that installs C6 on devices - I have
      used it on sata drives, ssds and

      CF. The first thing I do is dd of=$DRIVE if=/dev/zero bs=1024
      count=1 to wipe out the existing

      partition table then I do

      # 1MB = 2048 512byte sectors

      DSIZE=`sfdisk -s -uS $DRIVE`

      DSIZE=$((DSIZE*2))

      Log "DSIZE is $DSIZE"

      #OFFSET=2048

      OFFSET=8

      SWAP=1000000

      BOOT=600000

      PSIZE=$(((DSIZE-(OFFSET+BOOT+SWAP+10))/2))

      PSIZE=$((PSIZE+(PSIZE%2)))

      PSTART=$((PSIZE+BOOT+SWAP+OFFSET))

      Log "PSIZE is $PSIZE"

      Log "PSTART is $PSTART"

      # partition the disk for /boot, swap, /

      #/sbin/sfdisk -q -uS $DRIVE << EOF

      #8,600000,L,*

      #,1000000,S

      #,,L

      #EOF

      /sbin/sfdisk -f -q -uS $DRIVE << EOF

      $OFFSET,$BOOT,L,*

      $((OFFSET+BOOT)),$SWAP,S

      $((OFFSET+BOOT+SWAP)),$PSIZE,L

      $PSTART,,L

      EOF

      I am creating two linux partitions and a swap partition.

      The swap is fixed and the two linux partitions are approximately

      equal. 

      I have had no problem booting C6 after doing this.

    -- 

      Stephen Clark

      NetWolves

      Sr. Software Engineer III

      Phone: 813-579-3200

      Fax: 813-882-0209

      Email: steve.clark@xxxxxxxxxxxxx

      http://www.netwolves.com

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