Hi all. I have a CentOS server: CentOS release 5.7 (Final) 2.6.18-274.3.1.el5 x86_64 I have two SSD disks attached: smartctl -i /dev/sdc smartctl version 5.38 [x86_64-redhat-linux-gnu] Copyright (C) 2002-8 Bruce Allen Home page is http://smartmontools.sourceforge.net/ === START OF INFORMATION SECTION === Device Model: INTEL SSDSA2CW120G3 Serial Number: CVPR13010957120LGN Firmware Version: 4PC10362 User Capacity: 120,034,123,776 bytes Device is: Not in smartctl database [for details use: -P showall] ATA Version is: 8 ATA Standard is: ATA-8-ACS revision 4 Local Time is: Mon May 28 13:12:18 2012 CEST SMART support is: Available - device has SMART capability. SMART support is: Enabled smartctl -i /dev/sdd smartctl version 5.38 [x86_64-redhat-linux-gnu] Copyright (C) 2002-8 Bruce Allen Home page is http://smartmontools.sourceforge.net/ === START OF INFORMATION SECTION === Device Model: INTEL SSDSA2CW120G3 Serial Number: CVPR126101YK120LGN Firmware Version: 4PC10362 User Capacity: 120,034,123,776 bytes Device is: Not in smartctl database [for details use: -P showall] ATA Version is: 8 ATA Standard is: ATA-8-ACS revision 4 Local Time is: Mon May 28 13:12:35 2012 CEST SMART support is: Available - device has SMART capability. SMART support is: Enabled fdisk shows: fdisk -l /dev/sdc Disk /dev/sdc: 120.0 GB, 120034123776 bytes 32 heads, 32 sectors/track, 228946 cylinders Units = cylinders of 1024 * 512 = 524288 bytes Device Boot Start End Blocks Id System /dev/sdc1 3 491 250368 83 Linux /dev/sdc2 492 228946 116968960 fd Linux raid autodetect fdisk -l /dev/sdd Disk /dev/sdd: 120.0 GB, 120034123776 bytes 255 heads, 63 sectors/track, 14593 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Device Boot Start End Blocks Id System hdparm shows: hdparm -I /dev/sdc > ~/tmp/hdparm_sdc (file attached) hdparm -I /dev/sdd > ~/tmp/hdparm_sdd (file attached) diff hdparm_sd[cd] 2c2 < /dev/sdc: --- > /dev/sdd: 6c6 < Serial Number: CVPR13010957120LGN --- > Serial Number: CVPR126101YK120LGN 85c85 < Logical Unit WWN Device Identifier: 5001517959613b9f --- > Logical Unit WWN Device Identifier: 50015179595b6a83 88c88 < Unique ID : 959613b9f --- > Unique ID : 9595b6a83 hdparm -g /dev/sdc /dev/sdd /dev/sdc: geometry = 14593/255/63, sectors = 234441648, start = 0 /dev/sdd: geometry = 14593/255/63, sectors = 234441648, start = 0 sfdisk shows: sfdisk -g /dev/sdc;sfdisk -G /dev/sdc /dev/sdc: 14593 cylinders, 255 heads, 63 sectors/track !!!! /dev/sdc: 228946 cylinders, 32 heads, 32 sectors/track !!!! sfdisk -g /dev/sdd;sfdisk -G /dev/sdd /dev/sdd: 14593 cylinders, 255 heads, 63 sectors/track /dev/sdd: 14593 cylinders, 255 heads, 63 sectors/track I have /dev/sdc{1,2} mounted and used by /dev/md0, /dev/md1 RAID1. I would like to add /dev/sdd{1,2} to these RAID's but sfdisk has problems when I try to make partitions on /dev/sdd. sfdisk -d /dev/sdc | sfdisk /dev/sdd Checking that no-one is using this disk right now ... OK Disk /dev/sdd: 14593 cylinders, 255 heads, 63 sectors/track Old situation: Units = cylinders of 8225280 bytes, blocks of 1024 bytes, counting from 0 Device Boot Start End #cyls #blocks Id System /dev/sdd1 0 - 0 0 0 Empty /dev/sdd2 0 - 0 0 0 Empty /dev/sdd3 0 - 0 0 0 Empty /dev/sdd4 0 - 0 0 0 Empty Warning: given size (233937920) exceeds max allowable size (233933761) sfdisk: bad input As I see in fdisk's and sfdisk output there is a difference at some level in disk geometry. Could you suggest a solution? Best regards, Rafal.