[jira] [Resolved] (IMPALA-5858) Impalad misleadingly reports RAM as a rotational disk

["Tim Armstrong (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/IMPALA-5858?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Tim Armstrong resolved IMPALA-5858.
-----------------------------------
    Resolution: Won't Fix

> Impalad misleadingly reports RAM as a rotational disk
> -----------------------------------------------------
>
>                 Key: IMPALA-5858
>                 URL: https://issues.apache.org/jira/browse/IMPALA-5858
>             Project: IMPALA
>          Issue Type: Bug
>          Components: Backend
>    Affects Versions: Impala 2.8.0
>         Environment: Ubuntu 16.04, Dell Optiplex 7050
> Linux xxxx-xxxx 4.4.0-36-generic #55-Ubuntu SMP Thu Aug 11 18:01:55 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux
>            Reporter: Zoram Thanga
>            Priority: Minor
>
> The informational startup log of impalad dumps a lot of information, including a report of all "disks" found on the system. The list of disks is obtained from /proc/partitions. For the entries in /proc/partitions, the code reads /sys/block/<device>/queue/rotational.
> I0828 18:51:42.251794 31104 init.cc:218] Cpu Info:
>   Model: Intel(R) Core(TM) i7-7700 CPU @ 3.60GHz
>   Cores: 8
>   Max Possible Cores: 8
>   L1 Cache: 32.00 KB (Line: 64.00 B)
>   L2 Cache: 256.00 KB (Line: 64.00 B)
>   L3 Cache: 8.00 MB (Line: 64.00 B)
>   Hardware Supports:
>     ssse3
>     sse4_1
>     sse4_2
>     popcnt
>     avx
>     avx2
>   Numa Nodes: 1
>   Numa Nodes of Cores: 0->0 | 1->0 | 2->0 | 3->0 | 4->0 | 5->0 | 6->0 | 7->0 |
> I0828 18:51:42.251799 31104 init.cc:219] Disk Info: 
>   Num disks 3: 
> *    ram (rotational=true)
>     sda (rotational=true)
>     sr (rotational=true)
> For HDDs and SSDs this makes sense. But for RAM, it does not. It does not help that the kernel itself will flag /sys/block/ram{#}/queue/rotational as 1.
> $ cat /sys/block/ram0/queue/rotational 
> 1
> $
> We probably should not report RAM as a disk, or special-case handling of RAM devices/partitions that show up in /proc/partitions.



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