lkml.org 
[lkml]   [2008]   [May]   [28]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: Performance Characteristics of All Linux RAIDs (mdadm/bonnie++)
Justin Piszcz wrote:
> Hardware:
>
> 1. Utilized (6) 400 gigabyte sata hard drives.
> 2. Everything is on PCI-e (965 chipset & a 2port sata card)
>
> Used the following 'optimizations' for all tests.
>
> # Set read-ahead.
> echo "Setting read-ahead to 64 MiB for /dev/md3"
> blockdev --setra 65536 /dev/md3
>
> # Set stripe-cache_size for RAID5.
> echo "Setting stripe_cache_size to 16 MiB for /dev/md3"
> echo 16384 > /sys/block/md3/md/stripe_cache_size
>
> # Disable NCQ on all disks.
> echo "Disabling NCQ on all disks..."
> for i in $DISKS
> do
> echo "Disabling NCQ on $i"
> echo 1 > /sys/block/"$i"/device/queue_depth
> done

Given that one of the greatest benefits of NCQ/TCQ is with parity RAID,
I'd be fascinated to see how enabling NCQ changes your results. Of
course, you'd want to use a single SATA controller with a known good NCQ
implementation, and hard drives known to not do stupid things like
disable readahead when NCQ is enabled.

-- Chris


\
 
 \ /
  Last update: 2008-05-28 17:43    [W:2.056 / U:0.048 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site