[Fedora-livecd-list] persistence testing howto

[Douglas McClendon]

Mike Dickson wrote:
> Guys,
> 
> I got a LiveCD + Persistence usb drive running from your scripts, but 
> got I/O errors if I tried to do a yum update.
> 
> Before that I was able to vi test.txt and put some text in and it 
> survived a reboot.
> 
> What can I do to address the i/o errors?

My first question/explanation would be that you filled up the snapshot 
device.  This is quite possible, as a yum install involves creating 
several copies of the actual files you end up installing.

The way to see if this is what is happening would be to have another 
terminal open, and periodically watch the output of "dmsetup status". 
As new blocks are written to the rootfs snapshot device, you will see 
the snapshot filling up.

If you get these IO errors even before the snapshot fills up, please try 
to post some more detailed output.

In general, as discussed there are pros and cons with this method, and a 
unionfs method.  I do think there are ways to work around the cons of 
this method in such a way that it is useful.  For instance, I'll play 
around and see if I can prescribe a process of using yum that will get 
it to create all of its intermediate files in a native tmpfs (/dev/shm 
or the like) instead of the rootfs, so that they don't eat into the 
snapshot space.  Likewise, now that I have my first actual tester, maybe 
I'll figure out some other creative ways to improve the method (I have 
some ideas I need to experiment with...).

Thanks,

-dmc



> 
> MikeD
> 
> "Messsage from syslogd at localhost <mailto:syslogd at localhost> at
>   kernel: journal commit i/o error"
> 
> 
> On Wed, 2008-01-02 at 04:07 -0800, Mike Dickson wrote:
>> I have some time now.  I am attempting this tonight and tomorrow.  I 
>> will let you know.
>>
>> MikeD
>>
> 
> 
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