Slow disk I/O - was Re: Seeking Help [Ubuntu Bug??]

[Colin Law]

On 26 January 2013 20:10,  <geoff at thebakershome.net> wrote:
> I took a couple of days to backup all of my data and repartition my
> drives. I then installed 12.04 onto my 1 TB platter drive. It took only 12
> minutes (far faster than 12.10 on the SSD which was 6 hours).
>
> I rebooted into 12.04 and did an "apt-get"
>
> Fetched 1,001 kB in 4s (231 kB/s)
> Reading package lists... Done
>
> real    0m6.918s
> user    0m1.824s
> sys     0m0.128s
>
>
> It appears to me that there is a bug in Ubuntu 12.10 that was not present
> in 12.04.
>
> That same command in 12.10 takes 20 minutes.
>
> Anyone have any advice about what I should do next?

Plug in the SSD as well, but still boot 12.04 on the platter drive.
Then go to the SSD and exercise it with stuff that took a long time
before, assuming there was something other than apt-get that was slow.
 If necessary boot back on the SSD and find something else that is
slow first.  Obviously compare the times.

Colin

>
> I have 12.10 all setup the way I like, is there an easy way to move all
> that data to 12.04?
>
>
>> I do not know for sure. I get good benchmark sppeds in 12.10 as well. The
>> problem is when dealing with lots of small files (apt-get update,
>> compiling many files, etc).
>>
>> I do not know how to properly test this from the live 12.04 disk.
>>
>> I moved some data around on the hard drives overnight. Tonight I plan to
>> install 12.04 onto one of the platter drives. This should allow me to to a
>> proper test of the same commands (apt-get update) and better compare the
>> performance.
>>
>>>> I booted the 12.04 Ubuntu live disc and recorded some data.
>>>>
>>>> Disk Utility:
>>>>   All drives are detected as connected via SATA
>>>>     SSD Benchmark Results:
>>>>       Min Read Rate: 556.4 Mb/s
>>>>       Max Read Rate: 565.6 Mb/s
>>>>       Average Read Rate: 564.0 Mb/s
>>>>       Average Access Time: 0.1 ms
>>>
>>> Those are excellent results. So, are you saying the main issue is with
>>> the
>>> version of Ubuntu? That 12.04 works well, and 12.10 does not?
>>>
>>>
>>>
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>>
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>
>
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