[IMPALA-8188] Some SSDs are not properly detected as non-rotational

• Type: Bug
• Status: Resolved
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: Impala 3.2.0
• Fix Version/s: Impala 3.2.0
• Component/s: Backend
• Epic Color: ghx-label-5
• Assignee: Joe McDonnell
• Reporter: Joe McDonnell
• Created: 11/Feb/19 23:14
• Updated: 01/Apr/20 17:37
• Resolved: 27/Feb/19 18:03

Description

Here is an example Impala log:

 

I0211 10:50:40.650727 18344 init.cc:288] Disk Info: 
  Num disks 2: 
    nvme0n (rotational=true)
    nvme0n1p (rotational=true)

I logged into an equivalent machine, and the OS sees these as not rotational:

 

 

# cat /sys/block/nvme0n1/queue/rotational
0

Device names that end in a number get trimmed (i.e. /dev/sda2 becomes /dev/sda). See https://github.com/apache/impala/blob/master/be/src/util/disk-info.cc#L73-L74

These devices don't follow that pattern, so we don't find the right files. Neither /sys/block/nvme0n nor /sys/block/nvme0n1p exist, so both fall back to being rotational.

 

Issue Links

• is related to: IMPALA-7138 Fix detection and handling of Device Mapper volumes