Hi Colin, I can confirm that the Ubuntu 11.04 64-bit desktop release continues to exhibit this issue, and I have installer logs pinpointing exactly when this happened. The installation was done on a MacBook Pro with a WDC WD7500BPKT-75PK4T0 750 GB hard drive featuring Advanced Format 4096 blocks:
# cat /sys/block/sda/queue/physical_block_size 4096 # cat /sys/block/sda/queue/logical_block_size 512 Before starting, Mac OS X Snow Leopard was allocated 650 GB with the remaining 100 GB unallocated. I selected the automatic single click partitioning option in the graphical desktop Ubuntu installer assuming it would create boot, root and swap partitions in the remaining space, which it did without any intervention. However, while the boot and swap partitions it created were appropriately aligned, the main root partition (number 4) the installer created was unfortunately not aligned. This is a printout from gdisk: Disk /dev/disk0: 1465149168 sectors, 698.6 GiB Logical sector size: 512 bytes Disk identifier (GUID): *** Partition table holds up to 128 entries First usable sector is 34, last usable sector is 1465149134 Partitions will be aligned on 8-sector boundaries Total free space is 86 sectors (43.0 KiB) Number Start (sector) End (sector) Size Code Name 1 40 409639 200.0 MiB EF00 EFI System Partition 2 409640 1269940895 605.4 GiB AF00 Untitled 1 3 1269940896 1269942849 977.0 KiB EF02 4 1269942850 1456800271 89.1 GiB 0700 5 1456800272 1465149054 4.0 GiB 8200 As you can see, partition 4, the main Linux ext4 partition is not aligned. The Ubuntu disk utility has also identified this issue (screenshot with my serial number redacted attached): WARNING: The partition is misaligned by 3072 bytes. This may result in very poor performance. Repartitioning is suggested. Excerpt from the partman log where it created the misaligned partition: parted_server: Opening outfifo parted_server: requested partition with type primary parted_server: requested partition with file system ext4 parted_server: add_primary_partition(disk(1465149168),1269942850-1456800271) parted_server: OUT: OK I've no idea if this might have happened because the hardware or kernel mis-reported the optimal alignment, or if it's some other issue, but I would assume that the easy solution is to enforce 4096 alignment on all drives when partitioning automatically, as the benefit outweighs the potential loss of a megabyte or two. Let me know if you need the entire partman installer log or any other details. Also, please let me know if you find the issue so I can wipe the misaligned partition and re-install, as I'm only keeping it around to help diagnose this bug. ** Attachment added: "Misalignment warning screenshot" https://bugs.launchpad.net/ubuntu/+source/partman-base/+bug/756853/+attachment/2163039/+files/screenshot-misaligned-redacted.png -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/756853 Title: 11.04 beta aligns 4k disks on cylinder 63 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/partman-base/+bug/756853/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
