Read-only filesystem - should not be... how do I fix this?

[catlord17]

Hi ladies and gents, I need a but of guidance with this.  Here's the story.

A few months ago I went on a trip, and as a safety precaution in case my house burned down, I dismantled my external RAID mirror array and hid one disk in the house and took the other with me.  When I got back I could not remember where I hid the first one, but the one I took with me worked just fine.  Because I wasn't sure how the RAID controller would respond if I altered the contents of the disk I had, I did not add anything or erase anything while accessing this disk.

This morning, I stumbled upon the second disk and popped it into the RAID controller's second slot.  When I turned it on, the green lights came up showing each disk was responding, and I was able to mount them and decrypt them (whole disk encryption with TrueCrypt), and display contents, but I cannot alter the contents now because the filesystem is marked as read-only.

I tried checking the settings in TrueCrypt, and "Mount as read-only" was unchecked.  I tried doing a chkdsk on the disks and that revealed no errors. 

So, my question is twofold.  First, is this happening because I made some mistake and the contents of the first disk did get altered somehow?  And second, how do I fix this?  I need to make a system backup using this RAID set.

Thank you in advance for your help.  If there is any information you need in order to help, please ask, I don't know what you might need to know.

[djohnston]

Check the contents of /proc/mdstat. It's been a while since I used mdadm, but I believe

mdadm --readwrite /dev/(devicename)

will do the trick. However, before doing anything, read the mdadm man page. Also, have a look at this RedHat documentation.

[catlord17]

Thanks for your reply.  I have been having a bit of trouble getting a chance to reply here...

Long story short, I have mdadm installed via the lvm2 package.  When I attempt to issue the command, the result is as follows:

Code:

[shannon@localhost ~]$ su
Password:
[root@localhost shannon]# mdadm
bash: mdadm: command not found
[root@localhost shannon]#

This was the answer I got when I attempted to issue the command you suggested, as well, which was:

Code:

[root@localhost shannon]# mdadm --readwrite /dev/truecrypt3
bash: mdadm: command not found
[root@localhost shannon]#

I checked and found it was installed, so I uninstalled it and re-installed it (that way, not the "mark for re-installation" way), and this has not helped.  I am not sure what's wrong...

By the way, does it make any difference that this is a RAID controller external to the computer which is being attached via USB?

Again, thank you for your help.  I hope this isn't something I missed reading through the docs, or I'm gonna feel like a moron.

[djohnston]

Long story short, I have mdadm installed via the lvm2 package.  When I attempt to issue the command, the result is as follows:

Code:

[shannon@localhost ~]$ su
Password:
[root@localhost shannon]# mdadm
bash: mdadm: command not found
[root@localhost shannon]#

Okay, this is a complex setup you have. You have an external RAID array that is encrypted with TrueCrypt. Are you also using Logical Volume Manager? How many hard drives are we talking about? RAID0 or RAID1? What is the result of these two commands, both as a regular user, then as user root?

which mdadm
/sbin/mdadm --help
echo $PATH

[catlord17]

Long story short, I have mdadm installed via the lvm2 package.  When I attempt to issue the command, the result is as follows:

Code:

[shannon@localhost ~]$ su
Password:
[root@localhost shannon]# mdadm
bash: mdadm: command not found
[root@localhost shannon]#

Okay, this is a complex setup you have. You have an external RAID array that is encrypted with TrueCrypt. Are you also using Logical Volume Manager? How many hard drives are we talking about? RAID0 or RAID1? What is the result of these two commands, both as a regular user, then as user root?

which mdadm
/sbin/mdadm --help
echo $PATH

Here's what I know. 

I bought a 2-disk external drive bay which allows the disks to slide into it straight down, and bare, for good cooling.  It can be set up as JBOD, RAID-0 or RAID-1 and it connects to the laptop via USB.

I have two identical 2 TB hard drives which I inserted, set the controller to act in RAID-1 mode, and then used TrueCrypt to encrypt the whole RAID-1 array disc-at-once.  Not really familiar with Logical Volume Manager.

When I turn the array controller on, it has two lights, one for each disc, which can be red, yellow or green, and they can be solid or blink.  Red means no disk detected, yellow means something's wrong with a detected disk, and green means everything's working.  I am getting two green lights from these discs.  They are solid when the disks are not being accessed, and blink green when they are being accessed, just as is expected.

The output of your suggested access commands is as follows:

Code:

[root@localhost shannon]# which mdadm
which: no mdadm in (/sbin:/usr/sbin:/bin:/usr/bin:/usr/X11R6/bin:/usr/local/bin:/usr/local/sbin:/usr/lib/kde4/libexec:/usr/lib/qt4/bin:/usr/bin:/usr/sbin:/usr/lib/kde4/libexec:/bin:/sbin:/usr/X11R6/bin:/usr/games:/usr/local/bin:/usr/local/sbin)
'[root@localhost shannon]# /sbin/mdadm --help
bash: /sbin/mdadm: No such file or directory
[root@localhost shannon]# echo $path

[root@localhost shannon]#

I am beginning to wonder about mdadm, but shouldn't the external controller be handling this?

[djohnston]

Here's what I know.  

I bought a 2-disk external drive bay which allows the disks to slide into it straight down, and bare, for good cooling.  It can be set up as JBOD, RAID-0 or RAID-1 and it connects to the laptop via USB.

I have two identical 2 TB hard drives which I inserted, set the controller to act in RAID-1 mode, and then used TrueCrypt to encrypt the whole RAID-1 array disc-at-once.  Not really familiar with Logical Volume Manager.

When I turn the array controller on, it has two lights, one for each disc, which can be red, yellow or green, and they can be solid or blink.  Red means no disk detected, yellow means something's wrong with a detected disk, and green means everything's working.  I am getting two green lights from these discs.  They are solid when the disks are not being accessed, and blink green when they are being accessed, just as is expected.

I am beginning to wonder about mdadm, but shouldn't the external controller be handling this?

If you have mdadm installed, the executable will be /sbin/mdadm. If the executable isn't there, the package is not properly installed. Anyway, mdadm is used for setting up software RAID, which you clearly did not use. The hardware controller is the only thing you have relied on, according to your last post. The proper command for determining your search path is:

echo $PATH

Notice the capitalization. The dmraid utility may work with your controller, but I don't know.

1. What is the make and model of your RAID external device?
2. Did you get a hardware manual and utilities disk with the RAID controller?
3. What does TrueCrypt currently say about the RAID?
4. As user root, what is the output from the command cat /proc/mdstat?
5. Post the results of ls -l /media.