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Rizwan

Partition does not start on physical sector boundary.

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Hi,

I have SSD of size 480 GB and I have made a one partition of it. After making the single partition, when I tried 'fdisk -l' command, I am seeing the following output.

fdisk -l

Disk /dev/sda: 480.1 GB, 480103981056 bytes
255 heads, 63 sectors/track, 58369 cylinders, total 937703088 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk identifier: 0x00000000

Device Boot Start End Blocks Id System
/dev/sda1 1 937697984 468848992 83 Linux
Partition 1 does not start on physical sector boundary.

The error "Partition 1 does not start on physical sector boundary." is also displayed.

It seems to be strange. I have tried paritioning the SSD to four partitions but still the same error is repeating for other partititons as well.

Can any one help me on this. Thanks in advance

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Start 1 makes me think you need to use fdisk with compatibility options. Try fdisk -c -u

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Hi Kdawgca,

Thank you for the reply.

Using 'fdisk -c -u' have no luck.

If you can observe the output of 'fdisk -l' which I have provided earlier shows

Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes

Here the 'logical' sector size is 512 bytes and physical sector size is 4096 bytes. Whether this will have any impact.

Any idea whether we need to pass any options while formatting the disk either with 'fdisk' or 'sfdisk'.

Please help me. Thanks in advance.

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Hmm...give -lu a shot and see if it reports the same as -cu.

If it is a tool reporting issue, then you will want to find the most up to date tool/package....between fdisk/sfdisk and even cfdisk(supposedly less errors) IDK. I have always used gparted but mainly used it for other partition needs.

Alignment is the key here, but AFAIK the alignment looks fine as far as I can tell. 1*512/8(some use 512 other use 4096 but it is all a multiple of 8) = 64 which is an integer so you should be fine. Look into partition alignment and advance formats 4k, if you want to learn more as I am far from an expert. There might be a better way to check it depending on the distro.

If you want to try something then 1) try the below alignment method and 2) check the tools to see if they report anything different.

http://lifehacker.com/5837769/make-sure-your-partitions-are-correctly-aligned-for-optimal-solid-state-drive-performance

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