On Tue, 25 Dec 2007, Bill Davidsen wrote:
The issue I'm thinking about is hardware sector size, which on modern drives
may be larger than 512b and therefore entail a read-alter-rewrite (RAR) cycle
when writing a 512b block.
i'm not sure any shipping SATA disks have larger than 512B sectors
On Sat, 29 Dec 2007, dean gaudet wrote:
On Tue, 25 Dec 2007, Bill Davidsen wrote:
The issue I'm thinking about is hardware sector size, which on modern drives
may be larger than 512b and therefore entail a read-alter-rewrite (RAR) cycle
when writing a 512b block.
i'm not sure any shipping
Justin Piszcz wrote:
[]
Good to know/have it confirmed by someone else, the alignment does not
matter with Linux/SW RAID.
Alignment matters when one partitions Linux/SW raid array.
If the inside partitions will not be aligned on a stripe
boundary, esp. in the worst case when the filesystem
Robin Hill wrote:
On Wed Dec 19, 2007 at 09:50:16AM -0500, Justin Piszcz wrote:
The (up to) 30% percent figure is mentioned here:
http://insights.oetiker.ch/linux/raidoptimization.html
That looks to be referring to partitioning a RAID device - this'll only
apply to hardware RAID or
On Thu, 20 Dec 2007, Bill Davidsen wrote:
Justin Piszcz wrote:
On Wed, 19 Dec 2007, Bill Davidsen wrote:
I'm going to try another approach, I'll describe it when I get results (or
not).
http://home.comcast.net/~jpiszcz/align_vs_noalign/
Hardly any difference at whatsoever, only on the
On Wed, 19 Dec 2007, Justin Piszcz wrote:
--
Now to my setup / question:
# fdisk -l /dev/sdc
Disk /dev/sdc: 150.0 GB, 150039945216 bytes
255 heads, 63 sectors/track, 18241 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x5667c24a
Device Boot Start
On Wed, 19 Dec 2007, Mattias Wadenstein wrote:
On Wed, 19 Dec 2007, Justin Piszcz wrote:
--
Now to my setup / question:
# fdisk -l /dev/sdc
Disk /dev/sdc: 150.0 GB, 150039945216 bytes
255 heads, 63 sectors/track, 18241 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk
On 12/19/07, Justin Piszcz [EMAIL PROTECTED] wrote:
On Wed, 19 Dec 2007, Mattias Wadenstein wrote:
From that setup it seems simple, scrap the partition table and use the
disk device for raid. This is what we do for all data storage disks (hw
raid)
and sw raid members.
/Mattias
On Wed, 19 Dec 2007, Jon Nelson wrote:
On 12/19/07, Justin Piszcz [EMAIL PROTECTED] wrote:
On Wed, 19 Dec 2007, Mattias Wadenstein wrote:
From that setup it seems simple, scrap the partition table and use the
disk device for raid. This is what we do for all data storage disks (hw raid)
Justin Piszcz wrote:
On Wed, 19 Dec 2007, Mattias Wadenstein wrote:
On Wed, 19 Dec 2007, Justin Piszcz wrote:
--
Now to my setup / question:
# fdisk -l /dev/sdc
Disk /dev/sdc: 150.0 GB, 150039945216 bytes
255 heads, 63 sectors/track, 18241 cylinders
Units = cylinders of 16065 * 512
On Wed, 19 Dec 2007, Bill Davidsen wrote:
Justin Piszcz wrote:
On Wed, 19 Dec 2007, Mattias Wadenstein wrote:
On Wed, 19 Dec 2007, Justin Piszcz wrote:
--
Now to my setup / question:
# fdisk -l /dev/sdc
Disk /dev/sdc: 150.0 GB, 150039945216 bytes
255 heads, 63 sectors/track,
On 12/19/07, Bill Davidsen [EMAIL PROTECTED] wrote:
As other posts have detailed, putting the partition on a 64k aligned
boundary can address the performance problems. However, a poor choice of
chunk size, cache_buffer size, or just random i/o in small sizes can eat
up a lot of the benefit.
On 12/19/07, Bill Davidsen [EMAIL PROTECTED] wrote:
As other posts have detailed, putting the partition on a 64k aligned
boundary can address the performance problems. However, a poor choice of
chunk size, cache_buffer size, or just random i/o in small sizes can eat
up a lot of the benefit.
Justin Piszcz wrote:
On Wed, 19 Dec 2007, Bill Davidsen wrote:
Justin Piszcz wrote:
On Wed, 19 Dec 2007, Mattias Wadenstein wrote:
On Wed, 19 Dec 2007, Justin Piszcz wrote:
--
Now to my setup / question:
# fdisk -l /dev/sdc
Disk /dev/sdc: 150.0 GB, 150039945216 bytes
255 heads,
On Wed, 19 Dec 2007, Bill Davidsen wrote:
Justin Piszcz wrote:
On Wed, 19 Dec 2007, Bill Davidsen wrote:
Justin Piszcz wrote:
On Wed, 19 Dec 2007, Mattias Wadenstein wrote:
On Wed, 19 Dec 2007, Justin Piszcz wrote:
--
Now to my setup / question:
# fdisk -l /dev/sdc
Disk
On Wed, 19 Dec 2007, Bill Davidsen wrote:
I'm going to try another approach, I'll describe it when I get results (or
not).
http://home.comcast.net/~jpiszcz/align_vs_noalign/
Hardly any difference at whatsoever, only on the per char for read/write
is it any faster..?
Average of 3 runs
On Wed Dec 19, 2007 at 09:50:16AM -0500, Justin Piszcz wrote:
The (up to) 30% percent figure is mentioned here:
http://insights.oetiker.ch/linux/raidoptimization.html
That looks to be referring to partitioning a RAID device - this'll only
apply to hardware RAID or partitionable software RAID,
On Wed, 19 Dec 2007, Robin Hill wrote:
On Wed Dec 19, 2007 at 09:50:16AM -0500, Justin Piszcz wrote:
The (up to) 30% percent figure is mentioned here:
http://insights.oetiker.ch/linux/raidoptimization.html
That looks to be referring to partitioning a RAID device - this'll only
apply to
On 12/19/07, Michal Soltys [EMAIL PROTECTED] wrote:
Justin Piszcz wrote:
Or is there a better way to do this, does parted handle this situation
better?
What is the best (and correct) way to calculate stripe-alignment on the
RAID5 device itself?
Does this also apply to Linux/SW
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