Zoram Thanga created IMPALA-5858:
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Summary: 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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