Partition 1 does not start on physical sector boundary

[dendi]

Hello,

I just install a new pve 6 node on a single ssd.

I'm not an expert on disk stuff, but I see this ssd has a physical sector size of 4096, so I think all partition must begin with a 4096 multiple sector size, isn't it?

But fdisk warn me only for partition 1.
Partition 2 and 3 are 2048 multiple, nt 4096 multiple but get no warnings.

With PVE6 installer I set 60 GB hd because I want to add a drbdpool vg on a new partition

Thanks for your suggestions

fdisk -l
Disk /dev/sda: 894.3 GiB, 960197124096 bytes, 1875385008 sectors
Disk model: SAMSUNG MZ7LH960
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: gpt

Device       Start       End   Sectors  Size Type
/dev/sda1       34      2047      2014 1007K BIOS boot
/dev/sda2     2048   1050623   1048576  512M EFI System
/dev/sda3  1050624 125829120 124778497 59.5G Linux LVM

Partition 1 does not start on physical sector boundary.


Disk /dev/mapper/pve-root: 27.5 GiB, 29523705856 bytes, 57663488 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 /dev/mapper/pve-swap: 32 GiB, 34359738368 bytes, 67108864 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

 

[Stoiko Ivanov]

partition one created by the PVE-installer is used for legacy/BIOS booting from a GPT partitioned drive.
since it seldomly gets written to (grub updates only) the alignment check should be harmless (for this partition)!

regarding the multiple of 2048 vs. 4096 - AFAIR `parted` only checks for alignment on 1M (=2048 * 512b blocks)

I hope this helps!

 

[dendi]

Thank you for your reply, Stoiko.
2048*512b... yes, I missed it!

 

[eagle2020]

Just for clarification:
my config is (same as of the scond mirrored disk):
Disk /dev/sdb: 1.75 TiB, 1920383410176 bytes, 3750748848 sectors
Disk model: SAMSUNG MZ7L31T9
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: gpt
Disk identifier: 3B65C85B-244A-454D-B65E-4BE127EBA619

Device Start End Sectors Size Type
/dev/sdb1 34 2047 2014 1007K BIOS boot
/dev/sdb2 2048 1050623 1048576 512M EFI System
/dev/sdb3 1050624 3750748814 3749698191 1.7T Solaris /usr & Apple ZFS

/dev/sdb3 is a write intensive partition but starts at 1050624/4096 = 256.5!
Should I care about for the sake of performance, or is this tiopic not relevant for a SSD?

The allignment was done by the proxmox installer.

Kind Regards,
Frank