Hi! I just got a few servers with PM983 NVMe disks. I’m going to run ZFS on them, but I’m not sure what setting I should use for ashift.
ZFS uses ashift=9 by default as that is what the disks report, but when using smartctl -a this is what I get:
smartctl 7.1 2019-12-30 r5022 [x86_64-linux-5.4.0-42-generic] (local build) Copyright (C) 2002-19, Bruce Allen, Christian Franke, www.smartmontools.org === START OF INFORMATION SECTION === Model Number: SAMSUNG MZ1LB1T9HALS-00007 Serial Number: SXXXXXXXXXXXX Firmware Version: EDA7602Q PCI Vendor/Subsystem ID: 0x144d IEEE OUI Identifier: 0x002538 Total NVM Capacity: 1,920,383,410,176 [1.92 TB] Unallocated NVM Capacity: 0 Controller ID: 4 Number of Namespaces: 1 Namespace 1 Size/Capacity: 1,920,383,410,176 [1.92 TB] Namespace 1 Utilization: 225,070,653,440 [225 GB] Namespace 1 Formatted LBA Size: 512 Local Time is: Sat Oct 17 18:17:29 2020 UTC Firmware Updates (0x17): 3 Slots, Slot 1 R/O, no Reset required Optional Admin Commands (0x000f): Security Format Frmw_DL NS_Mngmt Optional NVM Commands (0x001f): Comp Wr_Unc DS_Mngmt Wr_Zero Sav/Sel_Feat Maximum Data Transfer Size: 512 Pages Warning Comp. Temp. Threshold: 86 Celsius Critical Comp. Temp. Threshold: 87 Celsius Namespace 1 Features (0x02): NA_Fields Supported Power States St Op Max Active Idle RL RT WL WT Ent_Lat Ex_Lat 0 + 8.00W - - 0 0 0 0 0 0 Supported LBA Sizes (NSID 0x1) Id Fmt Data Metadt Rel_Perf 0 + 512 0 0 1 - 4096 0 0 === START OF SMART DATA SECTION === SMART overall-health self-assessment test result: PASSED SMART/Health Information (NVMe Log 0x02) Critical Warning: 0x00 Temperature: 27 Celsius Available Spare: 100% Available Spare Threshold: 10% Percentage Used: 0% Data Units Read: 779,217 [398 GB] Data Units Written: 1,317,842 [674 GB] Host Read Commands: 1,217,818 Host Write Commands: 15,005,794 Controller Busy Time: 13 Power Cycles: 40 Power On Hours: 584 Unsafe Shutdowns: 33 Media and Data Integrity Errors: 0 Error Information Log Entries: 5 Warning Comp. Temperature Time: 0 Critical Comp. Temperature Time: 0 Temperature Sensor 1: 27 Celsius Temperature Sensor 2: 34 Celsius Temperature Sensor 3: 47 Celsius Error Information (NVMe Log 0x01, max 64 entries) No Errors Logged
Does the drive work with both 512B and 4096B internally, or what does this mean? What setting should I use for ashift? Most writes will likely be from MariaDB/MySQL(16KB).