[Live-demo] Re: [OSGeo] #808: USB, Persistant file system corruption

[OSGeo]

#808: USB, Persistant file system corruption
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 Reporter:  micha    |       Owner:  live-demo@…              
     Type:  task     |      Status:  new                      
 Priority:  normal   |   Milestone:  Unplanned                
Component:  LiveDVD  |    Keywords:  5.0                      
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Comment(by hamish):

 Replying to [ticket:808 micha]:
 > I am making a batch of LiveUSB disks created with Unetbootin and using
 the
 > "persistence" option. I have found that I get file system corruption
 when using
 > the Desktop osgeo-halt icon to shutdown immediately after saving a new
 file.
 > If I wait a few moments (> 1 min) this does not occur.
 > If I shutdown using the usual shutdown in the top panel (under User's
 name) and
 > *wait for the 30 sec timeout*, the file system stays intact. But using
 the Desktop
 > shutdown icon, whatever directory I saved a file in becomes inaccessible
 on the
 > next boot.

 try adding `sync` near the start of /etc/init.d/umountfs (or has ubuntu
 upstart'd that?)

 the disk cache in linux defaults to waiting a maximum of 30 seconds before
 writing data to the disk. see /proc/sys/vm/dirty_expire_centisecs

 (actually for full safety wait >35 sec just to be sure pdflush has run)

 running `sync` makes it write out everything immediately and not wait for
 the timeout.


 probably should be filed upstream in launchpad as an ubuntu bug. (if not
 there already)


 Hamish

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Ticket URL: <https://trac.osgeo.org/osgeo/ticket/808#comment:1>
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