in my previous test, using SATA, i got better result in 2.6 instead of
2.4. :P
Ming
On Fri, 2005-07-15 at 06:01 +, Holger Kiehl wrote:
I'm trying to figure out why the last two numbers differ.
Have you checked what the performance with a 2.4.x kernel is? If I
remember correctly there
On Wed, 2005-07-13 at 23:58 -0400, Dan Christensen wrote:
David Greaves [EMAIL PROTECTED] writes:
In my setup I get
component partitions, e.g. /dev/sda7: 39MB/s
raid device /dev/md2: 31MB/s
lvm device /dev/main/media: 53MB/s
(oldish system - but note that
my problem here. this only apply to sdX not mdX. pls ignore this.
ming
On Thu, 2005-07-14 at 08:30 -0400, Ming Zhang wrote:
Also, is there a way to disable caching of reads? Having to clear
the cache by reading 900M each time slows down testing. I guess
I could reboot with mem=100M, but
Mark Hahn [EMAIL PROTECTED] writes:
Is there a way for me to simulate readahead in userspace, i.e. can
I do lots of sequential asynchronous reads in parallel?
there is async IO, but I don't think this is going to help you much.
Also, is there a way to disable caching of reads? Having to
i also want a way to clear part of the whole page cache by file id. :)
understandably, kernel developers are don't high-prioritize this sort of
not-useful-for-normal-work feature.
i also want a way to tell the cache distribution, how many for file A
and B,
you should probably try
Ming Zhang [EMAIL PROTECTED] writes:
On Thu, 2005-07-14 at 19:29 -0400, Mark Hahn wrote:
i also want a way to clear part of the whole page cache by file id. :)
understandably, kernel developers are don't high-prioritize this sort of
not-useful-for-normal-work feature.
agree.
Clearing
On Tue, 2005-07-12 at 22:52 -0400, Dan Christensen wrote:
Ming Zhang [EMAIL PROTECTED] writes:
On Mon, 2005-07-11 at 11:11 -0400, Dan Christensen wrote:
I was wondering what I should expect in terms of streaming read
performance when using (software) RAID-5 with four SATA drives. I
Ming Zhang [EMAIL PROTECTED] writes:
have u try the parallel write?
I haven't tested it as thoroughly, as it brings lvm and the filesystem
into the mix. (The disks are in production use, and are fairly
full, so I can't do writes directly to the disk partitions/raid
device.)
My preliminary
On Wed, 2005-07-13 at 08:48 -0400, Dan Christensen wrote:
Ming Zhang [EMAIL PROTECTED] writes:
have u try the parallel write?
I haven't tested it as thoroughly, as it brings lvm and the filesystem
into the mix. (The disks are in production use, and are fairly
full, so I can't do writes
Ming Zhang [EMAIL PROTECTED] writes:
test on a production environment is too dangerous. :P
and many benchmark tool u can not perform as well.
Well, I put production in quotes because this is just a home mythtv
box. :-) So there are plenty of times when it is idle and I can do
benchmarks.
On Wed, 2005-07-13 at 10:23 -0400, Dan Christensen wrote:
Ming Zhang [EMAIL PROTECTED] writes:
test on a production environment is too dangerous. :P
and many benchmark tool u can not perform as well.
Well, I put production in quotes because this is just a home mythtv
box. :-) So there
Dan Christensen wrote:
Ming Zhang [EMAIL PROTECTED] writes:
test on a production environment is too dangerous. :P
and many benchmark tool u can not perform as well.
Well, I put production in quotes because this is just a home mythtv
box. :-) So there are plenty of times when it is
Here's a question for people running software raid-5: do you get
significantly better read speed from a raid-5 device than from it's
component partitions/hard drives, using the simple dd test I did?
Knowing this will help determine whether something is funny with my
set-up and/or hardware, or if
On Wed, 2005-07-13 at 19:02 +0100, David Greaves wrote:
Dan Christensen wrote:
Ming Zhang [EMAIL PROTECTED] writes:
test on a production environment is too dangerous. :P
and many benchmark tool u can not perform as well.
Well, I put production in quotes because this is
On Wed, 2005-07-13 at 22:18 +0100, David Greaves wrote:
Ming Zhang wrote:
component partitions, e.g. /dev/sda7: 39MB/s
raid device /dev/md2: 31MB/s
lvm device /dev/main/media: 53MB/s
(oldish system - but note that lvm device is *much* faster)
this is
On Wed, 2005-07-13 at 22:50 +0100, David Greaves wrote:
Ming Zhang wrote:
On Wed, 2005-07-13 at 22:18 +0100, David Greaves wrote:
Ming Zhang wrote:
component partitions, e.g. /dev/sda7: 39MB/s
raid device /dev/md2: 31MB/s
lvm device /dev/main/media:
On Wednesday July 13, [EMAIL PROTECTED] wrote:
Here's a question for people running software raid-5: do you get
significantly better read speed from a raid-5 device than from it's
component partitions/hard drives, using the simple dd test I did?
SCSI-160 bus, using just 4 of the 15000rpm
On Wednesday July 13, [EMAIL PROTECTED] wrote:
Question for the list: if I'm doing a long sequential write, naively
each parity block will get recalculated and rewritten several times,
once for each non-parity block in the stripe. Does the write-caching
that the kernel does mean that each
On Wednesday July 13, [EMAIL PROTECTED] wrote:
I guess each raw device does some readahead, then the md0 does some
readahead and then the lvm does some readahead. Theoretically the md0
and lvm should overlap - but I guess that much of the raw device level
readahead is discarded.
No. Devices
On Wednesday July 13, [EMAIL PROTECTED] wrote:
On Thu, 2005-07-14 at 08:38 +1000, Neil Brown wrote:
On Wednesday July 13, [EMAIL PROTECTED] wrote:
Here's a question for people running software raid-5: do you get
significantly better read speed from a raid-5 device than from it's
On Thu, 2005-07-14 at 11:16 +1000, Neil Brown wrote:
On Wednesday July 13, [EMAIL PROTECTED] wrote:
On Thu, 2005-07-14 at 08:38 +1000, Neil Brown wrote:
On Wednesday July 13, [EMAIL PROTECTED] wrote:
Here's a question for people running software raid-5: do you get
significantly
David Greaves [EMAIL PROTECTED] writes:
In my setup I get
component partitions, e.g. /dev/sda7: 39MB/s
raid device /dev/md2: 31MB/s
lvm device /dev/main/media: 53MB/s
(oldish system - but note that lvm device is *much* faster)
Did you test component device and
component partitions, e.g. /dev/sda7: 39MB/s
raid device /dev/md2: 31MB/s
lvm device /dev/main/media: 53MB/s
(oldish system - but note that lvm device is *much* faster)
Did you test component device and raid device speed using the
read-ahead settings tuned
On Mon, 2005-07-11 at 11:11 -0400, Dan Christensen wrote:
I was wondering what I should expect in terms of streaming read
performance when using (software) RAID-5 with four SATA drives. I
thought I would get a noticeable improvement compared to reads from a
single device, but that's not the
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