XPost: linux.debian.bugs.dist   
   From: carnil@debian.org   
      
   Control: tags -1 + moreinfo   
      
   Hi Filippo,   
      
   On Wed, Nov 19, 2025 at 01:46:21PM +0000, Filippo Giunchedi wrote:   
   > Source: linux   
   > Version: 6.12.57-1   
   > Severity: important   
   >   
   > Dear Maintainer,   
   > At Wikimedia Foundation we are running Trixie debian-installer on Dell r450   
   > hardware with an mpt3sas (HBA355i with id 1000:00e6) controller and SSD   
   > attached. While debian-installer finished successfully, grub was then unable   
   to   
   > boot the installed system.   
   >   
   > Partman is instructed to assemble a raid10 over four devices with LVM on top.   
   > Upon inspection the LVM PV is created with ~4GB metadata area which tricks   
   grub   
   > into allocating the same amount of memory during LVM detection. While   
   > grub-install taking ~4GB of RAM "works" during installation, albeit   
   > grub-install being quite slow, it obviously fails when booting.   
   >   
   > I tracked down the problem to md0 reporting optimal_io_size of ~4GB, and LVM   
   > defaults to align metadata with said size, resulting in abnormally large   
   > PV metadata area.   
   >   
   > The large md0 optimal_io_size seems to come from component devices reporting   
   > 16MB optimal_io_size as shown below.   
   >   
   > This host was working fine with Bookworm, which makes me think something has   
   > changed in mpt3sas.   
   >   
   > My understanding is that the controller queries devices via block limits VPD   
   > page for these values, and I'm attaching the output below. The original task   
   > which spawned this work is https://phabricator.wikimedia.org/T407586   
   >   
   > I'm happy to conduct further testing for bug fixes and/or investigation.   
   >   
   > best,   
   > Filippo   
   >   
   > ====   
   >   
   > # uname -a   
   > Linux cloudcontrol2010-dev 6.12.57+deb13-amd64 #1 SMP PREEMPT_DYNAMIC Debian   
   6.12.57-1 (2025-11-05) x86_64 GNU/Linux   
   >   
   > # lsblk -t   
   > NAME           ALIGNMENT MIN-IO     OPT-IO PHY-SEC LOG-SEC ROTA SCHED         
   RQ-SIZE      RA WSAME   
   > sda                    0   4096   16773120    4096     512    0   
   mq-deadline     256   32760    0B   
   > |-sda1                 0   4096   16773120    4096     512    0   
   mq-deadline     256   32760    0B   
   > |-sda2                 0   4096   16773120    4096     512    0   
   mq-deadline     256   32760    0B   
   > `-sda3                 0   4096   16773120    4096     512    0   
   mq-deadline     256   32760    0B   
   >   `-md0                0 524288 4293918720    4096     512       
                        4192256    0B   
   >     |-vg0-swap         0 524288 4293918720    4096     512       
                        4192256    0B   
   >     |-vg0-root         0 524288 4293918720    4096     512       
                        4192256    0B   
   >     `-vg0-srv          0 524288 4293918720    4096     512       
                        4192256    0B   
   > sdb                    0   4096   16773120    4096     512    0   
   mq-deadline     256   32760    0B   
   > |-sdb1                 0   4096   16773120    4096     512    0   
   mq-deadline     256   32760    0B   
   > |-sdb2                 0   4096   16773120    4096     512    0   
   mq-deadline     256   32760    0B   
   > `-sdb3                 0   4096   16773120    4096     512    0   
   mq-deadline     256   32760    0B   
   >   `-md0                0 524288 4293918720    4096     512       
                        4192256    0B   
   >     |-vg0-swap         0 524288 4293918720    4096     512       
                        4192256    0B   
   >     |-vg0-root         0 524288 4293918720    4096     512       
                        4192256    0B   
   >     `-vg0-srv          0 524288 4293918720    4096     512       
                        4192256    0B   
   > sdc                    0   4096   16773120    4096     512    0   
   mq-deadline     256   32760    0B   
   > |-sdc1                 0   4096   16773120    4096     512    0   
   mq-deadline     256   32760    0B   
   > |-sdc2                 0   4096   16773120    4096     512    0   
   mq-deadline     256   32760    0B   
   > `-sdc3                 0   4096   16773120    4096     512    0   
   mq-deadline     256   32760    0B   
   >   `-md0                0 524288 4293918720    4096     512       
                        4192256    0B   
   >     |-vg0-swap         0 524288 4293918720    4096     512       
                        4192256    0B   
   >     |-vg0-root         0 524288 4293918720    4096     512       
                        4192256    0B   
   >     `-vg0-srv          0 524288 4293918720    4096     512       
                        4192256    0B   
   > sdd                    0   4096   16773120    4096     512    0   
   mq-deadline     256   32760    0B   
   > |-sdd1                 0   4096   16773120    4096     512    0   
   mq-deadline     256   32760    0B   
   > |-sdd2                 0   4096   16773120    4096     512    0   
   mq-deadline     256   32760    0B   
   > `-sdd3                 0   4096   16773120    4096     512    0   
   mq-deadline     256   32760    0B   
   >   `-md0                0 524288 4293918720    4096     512       
                        4192256    0B   
   >     |-vg0-swap         0 524288 4293918720    4096     512       
                        4192256    0B   
   >     |-vg0-root         0 524288 4293918720    4096     512       
                        4192256    0B   
   >     `-vg0-srv          0 524288 4293918720    4096     512       
                        4192256    0B   
   >   
   >   
   > # pvck --dump headers /dev/md0   
   >   label_header at 512   
   >   label_header.id LABELONE   
   >   label_header.sector 1   
   >   label_header.crc 0xbdf3a961   
   >   label_header.offset 32   
   >   label_header.type LVM2 001   
   >   pv_header at 544   
   >   pv_header.pv_uuid KDkSuWsrIico15Y0PenxiLzT8Ad2dGLa   
   >   pv_header.device_size 1919546294272   
   >   pv_header.disk_locn[0] at 584 # location of data area   
   >   pv_header.disk_locn[0].offset 4293918720   
   >   pv_header.disk_locn[0].size 0   
   >   pv_header.disk_locn[1] at 600 # location list end   
   >   pv_header.disk_locn[1].offset 0   
   >   pv_header.disk_locn[1].size 0   
   >   pv_header.disk_locn[2] at 616 # location of metadata area   
   >   pv_header.disk_locn[2].offset 4096   
   >   pv_header.disk_locn[2].size 4293914624   
   >   pv_header.disk_locn[3] at 632 # location list end   
   >   pv_header.disk_locn[3].offset 0   
   >   pv_header.disk_locn[3].size 0   
   >   pv_header_extension at 648   
   >   pv_header_extension.version 2   
   >   pv_header_extension.flags 1   
      
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