[ale] why would it take longer to delete a file than tocreateit?

Fri May 7 17:17:53 EDT 2010

Iostats is reporting iowait in the 30%-50% range.  Its 17% since it was 
booted 223 days ago.

Well, I am in the process of setting up a replacement database server 
anyway. I just wanted to figure out what was wrong with the old machine so I 
could make sure I didn't make the same mistake on the new server. So I'll 
just put the new server into production and then figure out what I did wrong 
with the old server. And if I find out its something that makes me start 
over, I can just go back to the old server temporarily.

----- Original Message ----- 
From: "Greg Freemyer" <greg.freemyer at gmail.com>
To: "Atlanta Linux Enthusiasts - Yes! We run Linux!" <ale at ale.org>
Sent: Thursday, May 06, 2010 10:39 AM
Subject: Re: [ale] why would it take longer to delete a file than 
tocreateit?

John,

As a general statement, taking 3 minutes to create a 1GB file on an
active db server is not that slow.

I would not at all assume something is wrong based on that one test.

How many i/o's per second are you seeing with just db activity?

(iostat -d 1      is how I check that).

Greg

On Thu, May 6, 2010 at 11:18 AM, John G. Heim <jheim at math.wisc.edu> wrote:
> Well, I guess the *real* question is why is the system so loaded? I 
> believe
> its IO bound, based on my dd test, but I don't know why. Its running mysql
> with databases for horde3 and drupal. The slow query log is jammed with 
> slow
> update messages. But the DB server has 16 Gb of RAM and the entire size of
> the mysql data all together is only 3 Gb.
>
> I have to figure something is wrong at the OS level because of the slow dd
> thing and because I just don't have that much actual data. I think mysql
> ought to be able to handle this load like a breeze. I don't think mysql is
> slowing down the server. I think it's already slow and mysql is slow 
> because
> disk writes are so slow (for some reason).
>
> I think I'm going to move the mysql data to another machine temporarily 
> and
> turn off mysql and then run my test. I'll bet it speeds up but I'll bet it
> doesn't blaze.
>
> ----- Original Message -----
> From: "Greg Freemyer" <greg.freemyer at gmail.com>
> To: "Atlanta Linux Enthusiasts - Yes! We run Linux!" <ale at ale.org>
> Sent: Thursday, May 06, 2010 6:15 AM
> Subject: Re: [ale] why would it take longer to delete a file than to
> createit?
>
>
>> Michael,
>>
>> My phrasing was poor. I was trying to say what you said.
>>
>> Greg
>>
>>
>> On 5/5/10, Michael Trausch <mike at trausch.us> wrote:
>>> I don't quite understand that. Would it not be faster to perform such
>>> actions on an idle system as opposed to a loaded one?
>>>
>>> - mike
>>>
>>> --
>>> Sent from my ADP1 running Android 2.1
>>>
>>> On May 5, 2010 6:06 PM, "Greg Freemyer" <greg.freemyer at gmail.com> wrote:
>>>
>>> Is that on an idle disk/array?
>>>
>>> That would be very slow.
>>>
>>> But if its busy serving db queries, its not surprising.
>>>
>>>
>>> On Wed, May 5, 2010 at 4:45 PM, John G. Heim <jheim at math.wisc.edu> 
>>> wrote:
>>>> Doh! Caching... I shoul...
>>> --
>>> Greg Freemyer
>>> Head of EDD Tape Extraction and Processing team
>>> Litigation Triage Solutions Specialist
>>> http://www.linkedin.com/in/gregfreemyer
>>> CNN/TruTV Aired Forensic Imaging Demo -
>>>
>>> http://insession.blogs.cnn.com/2010/03/23/how-computer-evidence-gets-retrieved/
>>>
>>> The Norcross Group
>>> The Intersection of Evidence & Technology
>>> http://www.norcrossgroup.com
>>>
>>>
>>> _______________________________________________
>>> Ale mailing list
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>>
>> --
>> Sent from my mobile device
>>
>> Greg Freemyer
>> Head of EDD Tape Extraction and Processing team
>> Litigation Triage Solutions Specialist
>> http://www.linkedin.com/in/gregfreemyer
>> CNN/TruTV Aired Forensic Imaging Demo -
>>
>> http://insession.blogs.cnn.com/2010/03/23/how-computer-evidence-gets-retrieved/
>>
>> The Norcross Group
>> The Intersection of Evidence & Technology
>> http://www.norcrossgroup.com
>> _______________________________________________
>> Ale mailing list
>> Ale at ale.org
>> http://mail.ale.org/mailman/listinfo/ale
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>
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-- 
Greg Freemyer
Head of EDD Tape Extraction and Processing team
Litigation Triage Solutions Specialist
http://www.linkedin.com/in/gregfreemyer
CNN/TruTV Aired Forensic Imaging Demo -
   http://insession.blogs.cnn.com/2010/03/23/how-computer-evidence-gets-retrieved/

The Norcross Group
The Intersection of Evidence & Technology
http://www.norcrossgroup.com

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