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We are running a Ubuntu 10.04 VM on a Hyper-V system,
The VM is dedicated to running one of our web applications.

We have enabled the Hyper-V drivers in /etc/initramfs-tools/modules like so:


And updated the kernel image like so:

$ update-initramfs -u

And all was good... until..

This morning i got a support request that our web application was throwing an error 500, so i checked the logs and nothing was there.

Then I remembered that I had seen this on another of our ubuntu servers so I...

$ touch foo.txt

And my suspicions were confirmed:

touch:  cannot touch `foo.txt':  Read-only file system

Why is the filesystem randomly becoming readonly?

Is this only in Ubuntu on HV? Is it a problem on RedHat or Cent?

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up vote 1 down vote accepted

Can you check the log? Most likely the filesystem had errors, and went into read-only state because of it.

(Assuming you're using ext3 or ext4, as are Ubuntu's defaults:) You can adjust this behavior with the errors mount option.

errors=remount-ro is the default; errors=continue (to stay read-write at your own peril) and errors=panic (stop, drop, and roll crash) are your other options.

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This is a Hyper-V issue , hosts running Red Hat or Centos will have the same problems

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On what do you base this conclusion? Supporting documentation would be very helpful. – voretaq7 Apr 3 '12 at 17:33

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