HD sector size anomaly

Fdisk reports…

# fdisk /dev/sda

The device presents a logical sector size that is smaller than
the physical sector size. Aligning to a physical sector (or optimal
I/O) size boundary is recommended, or performance may be impacted.

Command (m for help): p

Disk /dev/sda: 500.1 GB, 500107862016 bytes
255 heads, 63 sectors/track, 60801 cylinders, total 976773168 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: 0xffce0322

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1            2048     4196351     2097152   82  Linux swap / Solaris
/dev/sda2   *     4196352    46139391    20971520   83  Linux
/dev/sda3        46141438   976754687   465306625    f  W95 Ext'd (LBA)
Partition 3 does not start on physical sector boundary.
/dev/sda5        46141440    88094719    20976640   83  Linux
/dev/sda6        88096768   104871935     8387584   83  Linux
/dev/sda7       104873984   734011391   314568704   83  Linux
/dev/sda8       734013440   750791409     8388985   83  Linux

… is this something I should repair, and if so how do I do it without losing data?

Thanks in advance.

And what is the device? Revolving disk, SSD, …?
And as you have as well as openSUSE 12.2 as openSUSE 12.3 in your signature, the great quiz is on again.

No reason for concern, as far as I can tell. The misaligned partition is the external partition. But logical partitions within that seem okay.

The use of 4K physical blocks is becoming common on the newer disks.

A greater problem is that if you put that disk in a USB drive enclosure, there’s a good chance it will show a logical block size of 4K. And since the partition table is based on logical block size, the partitioning will be shown wrongly.

I was not aware that partitioning might be different on SSD than on my revolving disk drive. My error.

And as you have as well as openSUSE 12.2 as openSUSE 12.3 in your signature, the great quiz is on again.

Well I do have both 12.2 and 12.3 on the same drive and still boot 12.2 occasionally. Should I report the problem separately, once for 12.2 and once for 12.3?

Thank you for correcting me.

Thanks for the speedy response. I should have noticed the warning earlier, but as I have been using the drive without any problems for some time now I didn’t go looking for possible errors.

It isn’t te partitioning, but the sector size. More down to the “hardware”. This is already getting more and more remote from the real sectors by the firmware layer in the disk controler on revolving disks, but on an SSD and other static memory devices it is of course pure emulation of the disk sectors of old.

You mght be aware that people who try to help like to know what version of openSUSE is involved. Sometimes people think that mentioning their openSUSE version in their signature is enough for this. I do not encourage this for two reasons:

  1. To begin with, when one can not find the information in the first paragraph of a question/problem, one must remember to scroll down to see if it is in the signature. When it is, and not open to debate, then one found it and can scroll back to the top.
  2. When someone changes his/her signature (e.g. when (s)he upgraded his system), the actual signature will be shown also in old posts, thus making those old posts ureliable (to say it polite).

In your case, the outcome of reading the signature was debatable. And no, it is of course not needed to report/ask twice. It is enough to say in the beginning that you see the phenomenon on 12.2 and 12.3 alike. This is about helping your potential helpers, not about buraucracy.