Hello All,

I have 4x8TB hard drives configured in RAID 5 and installed Centos7. The system boots after several restarts. Even after the system boots up it gets stuck/hangs in some time ( 10/15 mins ). I have tried to boot in single user mode and thought of taking the backup but the issue over here is
1. I am able to boot in single user mode with rw init=/bin/sh command at the boot entry with"e" option.
2. I am able to see the data from the shell (sh) prompt.
3. I am able to configure the network and assign the IP to communicate to the other machine.
4. But unable to transfer the data as it gives me an error as D Bus cannot be connected.
5. I tried to connect a external hard drive and it detects but doesnt get mounted in any of the partition /dev or /mnt. Cant check the fdisk as the command in single user mode doesnt work even if i check it the external hard drive doenst mount.
*So how can i retrieve the data? How can i repair the Operating System (Centos 7) in single user mode or rescue mode?

Your suggestions will be valuable.

The server when powered on it doesnt detect the RAID controller card on the first attempt, restarting it several time the RAID controller detects and the drives pop up. Its MEGA RAID 9260-4i.

Hi, and welcome here, at LQ
Unfortunately what you wrote is not really enough to help you.
2. What kind of data is it, what do you mean by see it?
4. how did you try to transfer what kind of data (from where/to where)?
5. how did you connect that external drive, how do you know it is detected, how did you try to mount it? How did you check it and what did you check at all?
What do you mean by fdisk does not work? Why do you want to repair your CentOS?
Did you try to run smartctl? Did you check your log files?
http://www.catb.org/~esr/faqs/smart-...html#beprecise

This is clearly a hardware issue. Trying to access the data using various software workarounds could easily do more harm than good.

Try disconnecting all drives and see if the system then detects the presence of the controller. If it does, you probably have a failing PSU.

If the issue persists, you need to rule out the controller as the source of the problem. Put it in a known working PC and see if it's reliably detected.

If the controller seems OK, try removing and re-seating the controller a few times and see if that makes a difference and, if possible, try it in different PCIe slots. Also, inspect the motherboard for bad capacitors.

Hi,

I shall elaborate it.

1. Those are data files which are in ASCII format and some are in scientific processing files. As explained the OS doesnt boot when i power on at once.. on repeated reboots the server pops up with the MEGA RAID 9260-4i with the 4 drives each of 8 TB capacity and then the OS options prompt, but when i select one of the kernel version the OS doesnt boot instead the cursor blinks. Now i reboot with ALT CTRL DEL and and repeat the entire process to boot the server. When i do it this way out of 5-6 times once the OS boots with the GUI screen and when i log in after few minutes the server hangs. So to take the data out and to repair this OS issue.

2. I have logged into single user mode. When i do it with "e" option and the shell prompt comes up i can view the home folders and the data files in it.

3. I was trying to copy the data which i can view by booting the server in single user mode to a External hard drive but the hard drive doesnt mount. It gets detected as when i plug in, it gives the details of the drive on the shell prompt. Seagate model number etc etc.

4. When the External drive didnt mount so i tried to transfer the data from server (where the data exists to be backedup) to another workstation with SCP command. To do it i had to configure the network by assigning the IP to the ethernet controller card (esp1f0) and i was able to ping the other workstaiton to which i thought of transferring the data. But as said an error popped with cannot read from /dev/urandom, no such file or directory. Sometimes it gives an error as Dbus connection error.

In single user mode when i tried with fdisk it didnt give me any output. The drives are intact and functioning no issue with the internal hard drives as such.

I thought there might be 2 reasons for this issue one with the RAID controller card or with the Operating System so if i can repair the OS instead of formatting the entire and reinstaling the OS.

if there are any other alternatives do kindly let me know. I just want to repair and boot the OS back without formatting.