View Issue Details
| ID | Project | Category | View Status | Date Submitted | Last Update |
|---|---|---|---|---|---|
| 0000615 | AlmaLinux-9 | linux-firmware | public | 2026-03-19 08:55 | 2026-03-19 10:23 |
| Reporter | ahmad-01 | Assigned To | |||
| Priority | normal | Severity | major | Reproducibility | always |
| Status | new | Resolution | open | ||
| Summary | 0000615: Linux reports optimal_io_size of 16776704 causing LVM data alignment inconsistency | ||||
| Description | Hi, I've been noticing LVM alignment inconsistencies and performance issues with SAS HDDs. I found out that sysfs is reporting 16776704 optimal_io_size even though the Disks' VPD does not report maximum transfer length. LVM is using this value to set the first physical extent of the physical volume. This does not align with the sector size of the disks of 4096 KB. I had to disable data alignment detection of LVM as a workaround. The SAS controller within the machine is "Broadcom / LSI Fusion-MPT 12GSAS/PCIe Secure SAS38xx [1000:00e6]" and kernel is 5.14.0-570.28.1.el9_6.x86_64. Thank you. | ||||
| Steps To Reproduce | check /sys/block/<device>/queue/optimal_io_size. Create LVM physical volume and check the location of the first Physical extent. | ||||
| Tags | No tags attached. | ||||
|
|
I have to add that the driver is mpt3sas: ``` 50:00.0 Serial Attached SCSI controller [0107]: Broadcom / LSI Fusion-MPT 12GSAS/PCIe Secure SAS38xx [1000:00e6] Subsystem: Dell HBA355i Adapter [1028:200b] Kernel driver in use: mpt3sas Kernel modules: mpt3sas ``` I have checked a different machine has a different SAS controller, with kernel version 5.14.0-570.41.1.el9_6.x86_64 and uses megaraid_sas driver: ``` 3b:00.0 RAID bus controller [0104]: Broadcom / LSI MegaRAID SAS-3 3108 [Invader] [1000:005d] (rev 02) Subsystem: Super Micro Computer Inc Device [15d9:0809] Kernel driver in use: megaraid_sas Kernel modules: megaraid_sas ``` This machine reports 0 optimal_io_size as expected and doesn't exhibit the alignment issue. |
